Terms in this set (23)

• Our Island, Earth
o Our Environment surrounds us
Environment: The sum total of our surroundings, including all of the living things and nonliving things with which we interact.
o Environmental science explores our interactions with the world
Environmental science: the scientific study of how the natural works, how our environment affects us, and how we affect our environment.
o We rely on natural resources
Natural resources: the substances and energy sources we take from our environment and that we rely on to survive.
Renewable natural resources: natural resources that are replenished over short periods of time.
Nonrenewable natural resources: natural resources that have a finite supply and are formed far more slowly than we use them. Once depleted nonrenewable resources is no longer available
Ecosystem services: an essential service and ecosystem provides that supports life and makes economic activity possible.
• For example, ecosystem naturally purify air and water, cycle nutrients, provide for plants to be pollinated by animals, and received and recycle the waste
o Population growth amplifies our impact
Agricultural revolution: people began to grow crops, domesticate animals, and live sedentary lives on farms and in villages, they produced more food to meet their nutritional needs and began having more children
Industrial revolution: a shift from rural life, animal powered agriculture, and handcrafted goods toward an urban society provisioned by mass production of factory-made goods and powered by fossil fuels
Fossil fuels: nonrenewable energy sources such as coal, oil, and natural gas
o Resource consumption exerts social and environmental pressures
Ecological footprint: expresses the cumulative area of biologically productive land and water required to provide the resources a person or population consumes and to dispose of or recycle the waste the person or population produces
Overshoot: the amount by which humanity's resource use, as measured by its ecological footprint, has surpassed Earth's long-term capacity to support us
o Environmental science can help us avoid past mistakes
• The Nature of Environmental Science
o Environmental science is interdisciplinary
Interdisciplinary: bringing techniques, perspectives, and research results from multiple disciplines together into a broad synthesis
Natural sciences: disciplines that examine the natural world
Social sciences: disciplines that address human interactions and institutions
Environmental studies: an academic environmental science program that emphasizes the social sciences as well as the natural sciences
o Environmental science is not the same as environmentalism
Environmentalism: the social movement dedicated to protecting the natural world- and, by extension, people from undesirable changes brought about by human actions
• The Nature of Science
Science: systematic process for learning about the world and testing our understanding of it
o Scientists test ideas by critically examining evidence
Observational science/ descriptive science: research in which scientists gather basic info about organisms, materials, systems, or processes that are not yet well known
Hypothesis-driven science: research that proceeds in a more targeted and structured manner, using experiments to test hypotheses within a framework traditionally known scientific method
o The scientific method is a traditional approach to research
Scientific method: a technique for testing ideas with observations
• Make observations
• Ask questions
• Develop a hypothesis
o Hypothesis: a statement that attempts to explain a phenomenon or answer a scientific question
• Make predictions
o Prediction: specific statements that can be directly and unequivocally tested
• Test the prediction
o Experiment: an activity designed to test the validity of a prediction or a hypothesis
o Variables: conditions that can change
o Independent variable: a variable the scientist manipulates
o Dependent variable: the variable that is affected by manipulation of the independent variable in an experiment
o Controlled experiment: an experiment in which a treatment is compared against a control in order to test the effect of a variable
o Control: the portion of an experiment in which a variable has been left unmanipulated, to serve as a point of comparison with the treatment
o Treatment: the portion of an experiment in which a variable has been manipulated in order to test its effects. Compare control.
• Analyze and interpret results
o Data: information, generally quantitative information
o We test hypotheses in different ways
Correlation: a statistical association among variables
o The scientific process continues beyond the scientific method
Peer Review
• Peer Review: the process by which a manuscript submitted for publication in an academic journal is examined by specialists in the field, who provide comments and criticism (generally anonymously) judge whether the work merits publication in the journal.
Conference presentations
Grants and funding
Repeatability
Theories
• Theories: a widely accepted, well-tested explanation of one or more cause-and-effect relationships that has been extensively validated by a great amount of research
o Science undergoes paradigm shifts
Paradigm: A dominant philosophical and theoretical framework within a scientific discipline.
• Environmental Ethics
Ethics: The academic study of good and bad, right and wrong. The term can also refer to a person's or group's set of moral principles or values.
Relativists: An ethicist who maintains that ethics do and should vary with social context. Compare universalist.
Universalists: An ethicist who maintains that there exist objective notions of right and wrong that hold across cultures and situations. Compare relativist.
Ethical standards: A criterion that helps differentiate right from wrong.
o Environmental ethics pertains to people and the environment
Anthropocentrism: A human-centered view of our relationship with the environment. Compare biocentrism and ecocentrism.
Biocentrism: A philosophy that ascribes relative values to actions, entities, or properties on the basis of their effects on all living things or on the integrity of the biotic realm in general. The biocentrist evaluates an action in terms of its overall impact on living things, including—but not exclusively focusing on—human beings. Compare anthropocentrism and ecocentrism.
Ecocentrism: A philosophy that considers actions in terms of their damage or benefit to the integrity of whole ecological systems, including both living and nonliving elements. For an ecocentrist, the well-being of an individual is less important than the long-term well-being of a larger integrated ecological system. Compare anthropocentrism and biocentrism.
o Conservation and preservation arose with 20th century
John Muir: Scottish immigrant to the United States who eventually settled in California and made the Yosemite Valley his wilderness home. Today, he is most strongly associated with the preservation ethic. He argued that nature deserved protection for its own inherent values but also claimed that nature facilitated human happiness and fulfillment.

Gifford Pinchot: The first professionally trained American forester, Pinchot helped establish the U.S. Forest Service. Today, he is the person most closely associated with the conservation ethic.

Conservation ethic: An ethic holding that people should put natural resources to use but also have a responsibility to manage them wisely. Compare preservation ethic.
o Aldo Leopold's land ethic inspires many people
Aldo Leopold: American scientist, scholar, philosopher, and author. His book The Land Ethic argued that humans should view themselves and the land itself as members of the same community and that humans are obligated to treat the land ethically.

o Environmental justice seeks fair treatment for all people
Environmental justice: The fair and equitable treatment of all people with respect to environmental policy and practice, regardless of their income, race, or ethnicity. Responds to the perception that minorities and the poor suffer more pollution than whites and the rich.
• Sustainability and Our future
Sustainability: A guiding principle of environmental science, entailing conserving resources, maintaining functional ecological systems, and developing long-term solutions, such that Earth can sustain our civilization and all life for the future, allowing our descendants to live at least as well as we have lived.
Natural capital: Earth's accumulated wealth of resources.
o Population and consumption drive environmental impact
o Energy choices will shape our future
o Sustainable solutions abound
Sustainable development: development that satisfies our current needs without compromising the future availability of natural capital or our future quality life
o Student are promoting solutions on campus
Campus sustainability: A term encompassing a wide variety of efforts by students, faculty, staff, and administrators of colleges and universities to make campus operations more sustainable. Includes efforts toward energy efficiency, water efficiency, emission reductions, transportation improvements, sustainable dining, landscaping improvements, renewable energy, curricular changes, and more.
Welcome to Environmental Science
Course introduction and resources
Brief lecture
Discussion of sustainability
Outline
Course introduction and resources
Activity: What are your issues?
Brief lecture
What is 'the environment'?
Case study: Rapa Nui (Easter Island)
Principles of sustainability
Human impact
Discussion: Are we on a sustainable path?
Course Introduction
Texts
Course resources on Blackboard
https://fairfield.blackboard.com/
Login using NetID and password
Online homework on Mastering system
http://www.masteringenvironmentalscience.com/
Register using CourseID and Access Code
What are your issues?
List what you view as the top three most important issues about the environment

Be prepared to explain why these made the list, and others didn't...
What is the 'environment'?
Environment: consists of all of the living and nonliving things around us.
Continents, oceans, clouds, and ice caps, animals, plants, etc.

All surroundings with which we interact:
Biotic: living things
Animals, plants, forests, fungi, etc.
Abiotic: Non-living things
Continents, oceans, clouds, soil, rocks
Buildings, human-created living centers
Social relationships and institutions
Perspectives on the environment
Ecosystem services support life
Humans are part of environment
Our survival depends on a healthy, functioning planet.

This is a fundamental insight of environmental science
Humans exist within the environment and are part of nature
Figure 1.2 Labeled
The case of Rapa Nui
Rapa Nui (Easter Island)
The most isolated inhabited island on Earth
Does this serve as a microscale model of global issues?
Polynesians originally settled the island in first centuries AD "Discovered" on Easter Sunday, 1722 by Dutch explorers Moai were rock statues raised vertically without metal tools

Principles of Sustainability
A sustainable society does not use natural resources or produce wastes faster than they are regenerated or assimilated by the environment

Principles of Sustainability
2. Society and the environment are interconnected, complex systems

Principles of Sustainability
3. Sustainable societies make decisions based on equity and fairness

Principles of Sustainability
4. Societies must have incentives and punishments to foster sustainable solutions


The I=PAT Equation
Human impact on the environment = population x affluence x technology
We are increasing our burden on the planet
Human population growth has accelerated
we add over 200,000 people to the planet per day

Consumption has risen even faster
a better quality of life cf. dawn of civilization

The rise in affluence has not been equal
global inequality has doubled in past 40 years

The Ecological Footprint
The resources and environmental services used to produce your food, clothing, shelter, and other goods and services
The cumulative area of biologically productive land and water required to provide the raw materials a person or population consumes and to dispose of or recycle the waste that is produced.
Your Ecological Footprint?
Drive a Car
Burn 1 liter gas (8000 kcals)
2 kg carbon emissions
¼ kg of carbon monoxide
Bicycle
Burn 210 kcals
Fewer emissions
Are we on a sustainable path?
"sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs."
— UN Bruntdland Commission, 1987
Resource use and replenishment
Industrial facilities
Catch per unit effort (fisheries)
Equitable and fair resource use?

Can Science Help?
What is science? yes
What is environmental science?
How is science used?
What is science?
Science focuses exclusively on the natural world, it does not deal with supernatural explanations.
Science is a way of learning about what is in the natural world, how the natural world works, and how the natural world got to be the way it is. It is not simply a collection of facts, but is also a path to understanding.
Scientists work in many different ways, but all science relies on testing ideas by figuring out what expectations are generated by an idea and making observations to find out whether those expectations hold true.

What is science? (cont.)
Accepted scientific ideas are reliable because they have been subjected to rigorous testing
As new evidence is acquired and new perspectives emerge ideas can be revised.
Science is a community endeavor. It relies on publication and peer review, which helps ensure that science moves in the direction of greater accuracy and understanding. This is facilitated by diversity within the scientific community, which offers a broad range of perspectives on scientific ideas.
Millennium Ecosystem Assessment (2005)
The most comprehensive scientific assessment of the condition of the world's ecological systems
Major findings:
Humans have drastically altered ecosystems;
Changes have contributed to human well-being and economic development, but at a cost;
Environmental degradation could get much worse;
Degradation can be reversed, but it requires work.
How is science used in society?
Science ≠ Technology

Science can inform or be distorted
Union of Concerned Scientists timeline on scientific integrity and political interference in the federal government

Pseudoscience (a.k.a. 'junk science') tries to masquerade as real science
Pheromones and the Athena Institute
Energy and Nutrients in Ecosystems
Energy flows through...
Nutrients cycle within
Physical laws are boundaries
Set limits on the processes and behaviors of environmental systems
Guide our understanding of structure of complex systems
Provide insight into some important environmental issues
Law of Conservation of Mass: The physical law stating that matter may be transformed from one type of substance into others, but that it cannot be created or destroyed.
Matter cannot be created or destroyed
but can be rearranged in form!
Assumption:
Closed system
Exception:
Mass defect in special relativity and quantum theory (E = mc2)
Lavoisier's laboratory
Laws of Thermodynamics
First Law of Thermodynamics
There is no change in the quantity of energy in any energy conversion
Second Law of Thermodynamics
In all conversion processes energy decreases in its ability to do work
Entropy increases, often as 'waste' heat
Third Law of Thermodynamics
You can never escape!
You can never break a law of physics
Energy Conversion Efficiency: The practice of reducing energy use as a way of extending the lifetime of our fossil fuel supplies, of being less wasteful, and of reducing our impact on the environment. Conservation can result from behavioral decisions or from technologies that demonstrate energy efficiency.
Ratio of work to total energy expended




Critical to understanding energy storage and use (by humans as well as other organisms)


A living power plant
Light energy input from the Sun


Photosynthesis: The process by which autotrophs produce their own food. Sunlight powers a series of chemical reactions that convert carbon dioxide and water into sugar (glucose), thus transforming low-quality energy from the sun into high-quality energy the organism can use.
Process used by majority of autotrophs to capture energy from the environment



Conversion of energy to stored organic compounds
Conversion efficiency?
Primary Production: The conversion of solar energy to the energy of chemical bonds in sugars during photosynthesis, performed by autotrophs. Compare secondary production.
The amount of chemical energy fixed by autotrophs per area • time
ex: g/m2•day
Gross primary production vs. net primary production
GPP = total energy fixed
NPP = GPP - energy used for maintenance and respiration losses
NPP is the amount of energy available to heterotrophs, and is therefore an important parameter in understanding living systems

Net primary productivity
NPP by biome
Autotrophs vs. Heterotrophs
Autotrophs- self feeding
Obtain energy from inorganic sources
photosynthesis
chemosynthesis
Input source of energy for living components of systems
Heterotrophs
Must consume organic material to obtain energy
Herbivores (plants)
Carnivores (animal)
Omnivores (both)
Detritivores (scavengers, eat dead or decaying material to get energy)

A savannah ecosystem
Energy flows
Nutrient cycles


Chemistry and Life
The connection between matter and energy
Atoms
Compounds are made of atoms
Macromolecules essential to life
Proteins
Build an organism
Gets things done
Carbohydrates
Sugar; starch
Energy storage molecules for living organisms
Lipids
Nucleic acids
DNA (at right)
RNA
Instructions to get stuff done
Food = chemical energy in bonds
Key Biogeochemical Cycles
Water, Carbon, Phosphorous & Nitrogen
Water
Carbon
Phosphorous
Nitrogen
Earth's Environmental Systems
System: a network of relationships among parts, elements, or components that interact with and influence one another through the exchange of energy, matter, or information
Lithosphere: the rock and sediment beneath our feet, the planet's uppermost mantle and crust
Atmosphere: composed of the air surrounding our planet
Hydrosphere: encompasses all water-salt or fresh; liquid, ice, or vapor- in surface bodies, underground, and in the atmosphere
Biosphere: consists of all planet's organisms and the abiotic (non-living) portions of the environment with which they interact
o Systems involve feedback loops
Feedback loop: a system's output can serve as input to the same system, a circular process
Negative feedback loop: A feedback loop in which output of one type acts as input that moves the system in the opposite direction. The input and output essentially neutralize each other's effects, stabilizing the system. Compare positive feedback loop.
Dynamic equilibrium: The state reached when processes within a system are moving in opposing directions at equivalent rates so that their effects balance out.
Homeostasis: The tendency of a system to maintain constant or stable internal conditions.
Positive feedback loops: A feedback loop in which output of one type acts as input that moves the system in the same direction. The input and output drive the system further toward one extreme or another. Compare negative feedback loop.
o Environmental Systems Interact
Runoff: The water from precipitation that flows into streams, rivers, lakes, and ponds, and (in many cases) eventually to the ocean.
Airshed: The geographic area that produces air pollutants likely to end up in a waterway.
Eutrophication: The process of nutrient enrichment, increased production of organic matter, and subsequent ecosystem degradation in a water body.
• Matter, Chemistry, and the Environmental
Matter: All material in the universe that has mass and occupies space. See law of conservation of matter.
Chemistry: The study of the different types of matter and how they interact.
Law of conservation of matter: The physical law stating that matter may be transformed from one type of substance into others, but that it cannot be created or destroyed
o Atoms and elements are chemical building blocks
Element: a fundamental type of matter, a chemical substance with a given set of properties, that cannot be chemically broken down into substances with either properties
Atoms: the smallest unit that maintains the chemically properties of an element
Protons: positively charged particles in the atom's nucleus (its dense center)
Neutrons: particles lacking electric charge in their nuclei
Electrons: A negatively charged particle that moves around the nucleus of an atom.
• ((hydrogen, oxygen, silicon, carbon, and nitrogen are abundant elements on the planet))\
• ((phosphorous, nitrogen, calcium, and carbon are nutrients because they are elements that organisms need for survival))
• nutrients: An element or compound that organisms consume and require for survival.
Isotopes: One of several forms of an element having differing numbers of neutrons in the nucleus of its atoms. Chemically, isotopes of an element behave almost identically, but they have different physical properties because they differ in mass.
Ions: An electrically charged atom or combination of atoms.
o Atoms bond to form molecules and compounds
Molecules: A combination of two or more atoms.
Chemical formula: A shorthand way to indicate the type and number of atoms in a molecule using numbers and chemical symbols.
Compound: A molecule whose atoms are composed of two or more elements.
Water: A compound composed of two hydrogen atoms bonded to one oxygen atom, denoted by the chemical formula H2O.
Carbon dioxide: a compound that consists of one carbon atom bonded to two oxygen atoms C2O
Ionic bonds: A type of chemical bonding where electrons are transferred between atoms, creating oppositely charged ions that bond due to their differing electrical charges. Table salt, or sodium chloride, is formed by the bonding of positively charged sodium ions with negatively charged chloride ions.
Covalent bonds: A type of chemical bonding where atoms share electrons in chemical bonds. An example is a water molecule, which forms when an oxygen atom shares electrons with two hydrogen atoms.
Solution: elements, molecules, and compounds that come together without chemically bonding
Methane: a colorless gas produced primarily by anaerobic decomposition. The major constituent of natural gas and greenhouse gas that is molecules for molecule more potent than carbon dioxide
Ozone: a molecule consisting of three atoms of oxygen. Absorbs UV radiation in the stratosphere
o The pH scale describes acids and bases
Acidic: the property of a solution in which the concentration of hydrogen ions is greater than the concentration of hydroxide ions
Neutral: 7 pure water
Basic: the property of a solution in which the concentration of hydroxide ions is greater than the concentration of hydrogen ions.
o Matter is composed of organic and inorganic compounds
organic compounds: A compound made up of carbon atoms (and, generally, hydrogen atoms) joined by covalent bonds and sometimes including other elements, such as nitrogen, oxygen, sulfur, or phosphorus. The unusual ability of carbon to build elaborate molecules has resulted in millions of different organic compounds showing various degrees of complexity.
Hydrocarbon: An organic compound consisting solely of hydrogen and carbon atoms.
o Macromolecules are building blocks of life
Polymers: A chemical compound or mixture of compounds consisting of long chains of repeated molecules. Important biological molecules, such as DNA and proteins, are examples of polymers.
Macromolecules: A very large molecule, such as a protein, nucleic acid, carbohydrate, or lipid.
Carbohydrates: An organic compound consisting of atoms of carbon, hydrogen, and oxygen.
Proteins: A macromolecule made up of long chains of amino acids.
Nucleic acids: A macromolecule that directs the production of proteins. Includes DNA and RNA.
Genes: A stretch of DNA that represents a unit of hereditary information.
Lipids: chemically diverse groups of compounds, classified together because they do not dissolve in water (fats and oils)
Cells: The most basic organizational unit of organisms.
• Energy Fundamentals
Energy: The capacity to change the position, physical composition, or temperature of matter; a force that can accomplish work
Potential energy: Energy of position. Compare kinetic energy.
Kinetic energy: Energy of motion. Compare potential energy.
Chemical energy: Potential energy held in the bonds between atoms.
o Energy is always conserved but it changes in quality
First law of thermodynamics: The physical law stating that energy can change from one form to another, but cannot be created or lost. The total energy in the universe remains constant and is said to be conserved.
Second law of thermodynamics: The physical law stating that the nature of energy tends to change from a more-ordered state to a less-ordered state; that is, entropy increases.
o Light Energy from the sun powers most living systems
Autotrophs (primary producer): An organism that can use the energy from sunlight to produce its own food. Includes green plants, algae, and cyanobacteria.
Producer: An organism that uses energy from sunlight to produce its own food. Includes green plants, algae, and cyanobacteria. See autotroph.
Photosynthesis: The process by which autotrophs produce their own food. Sunlight powers a series of chemical reactions that convert carbon dioxide and water into sugar (glucose), thus transforming low-quality energy from the sun into high-quality energy the organism can use. Compare cellular respiration.
o Cellular respiration release chemical energy
Cellular respiration: The process by which a cell uses the chemical reactivity of oxygen to split glucose into its constituent parts, water and carbon dioxide, and thereby release chemical energy that can be used to form chemical bonds or to perform other tasks within the cell. Compare photosynthesis.
Heterotrophs (consumer): An organism that consumes other organisms. Includes most animals, as well as fungi and microbes that decompose organic matter.
• Ecosystems
ecosystem: consists of all organisms and nonliving entities that occur and interact in a particular area at a particular time
o Energy flows and matter cycles through ecosystems
estuary: An area where a river flows into the ocean, mixing fresh water with salt water.
o Sunlight is converted to chemical energy in biomass
Primary production: The conversion of solar energy to the energy of chemical bonds in sugars during photosynthesis, performed by autotrophs. Compare secondary production.
Gross primary production: The energy that results when autotrophs convert solar energy (sunlight) to energy of chemical bonds in sugars through photosynthesis. Autotrophs use a portion of this production to power their own metabolism, which entails oxidizing organic compounds by cellular respiration. Compare net primary production.
Net primary production: The energy or biomass that remains in an ecosystem after autotrophs have metabolized enough for their own maintenance through cellular respiration. Net primary production is the energy or biomass available for consumption by heterotrophs. Compare gross primary production; secondary production.
Productivity: The rate at which plants convert solar energy (sunlight) to biomass. Ecosystems whose plants convert solar energy to biomass rapidly are said to have high productivity. See net primary productivity; gross primary production; net primary production.
Net primary productivity: The rate at which net primary production is produced. See productivity; gross primary production; net primary production; secondary production.
o Ecosystems interact across landscapes
Landscape ecology: The study of how landscape structure affects the abundance, distribution, and interaction of organisms. This approach to the study of organisms and their environments at the landscape scale focuses on broad geographical areas that include multiple ecosystems.
Patches: In landscape ecology, spatial areas within a landscape. Depending on a researcher's perspective, patches may consist of habitat for a particular organism, or communities, or ecosystems. An array of patches forms a mosaic.
Conversation biologist: A scientific discipline devoted to understanding the factors, forces, and processes that influence the loss, protection, and restoration of biodiversity within and among ecosystems.
o Modeling helps ecologists understand systems
Model: A simplified representation of a complex natural process, designed by scientists to help understand how the process occurs and to make predictions.
Ecological modeling: the practice of constructing and testing models that aim to explain and predict how ecological systems function
o Ecosystem services sustain our world
Ecosystem services: an essential service an ecosystem provides that supports life and makes economic activity possible. For example, ecosystems naturally purify air and water, cycle nutrients, provide for plants to be pollinated by animals, and receive and recycle waste we generate
• Biogeochemical cycles
o Nutrients circulate through ecosystems in biogeochemical cycles
Nutrient cycles (biogeochemical cycles): The comprehensive set of cyclical pathways by which a given nutrient moves through the environment.
o The water cycle affects all other cycles
Hydrologic cycle: The flow of water—in liquid, gaseous, and solid forms—through our biotic and abiotic environment. Also called the water cycle.
Evaporation: the conversion of a substance from a liquid to a gaseous form
Transpiration: the release of water vapor by plants, through their leaves
Precipitation: Water that condenses out of the atmosphere and falls to Earth in droplets or crystals.
Infiltration: permeation of a liquid into something by filtration
Aquifers: a body of permeable rock that can contain or transmit groundwater.
Groundwater: water held underground in the soil or in pores and crevices in rock
Water table: The upper limit of groundwater held in an aquifer.
o The carbon cycle circulates a vital organic nutrient
Carbon cycle: A major nutrient cycle consisting of the routes that carbon atoms take through the nested networks of environmental systems.
o The nitrogen cycle involves specialized bacteria
Nitrogen cycle: A major nutrient cycle consisting of the routes that nitrogen atoms take through the nested networks of environmental systems.
Nitrogen fixation: The process by which inert nitrogen gas combines with hydrogen to form ammonium ions (NH4+), which are chemically and biologically active and can be taken up by plants
Nitrogen- fixing bacteria: Bacteria that live independently in the soil or water, or those that form mutualistic relationships with many types of plants and provide nutrients to the plants by converting gaseous nitrogen to a usable form
Nitrification: The conversion by bacteria of ammonium ions (NH4+) first into nitrite ions (NO2-) and then into nitrate ions (NO3)
Denitrifying bacteria: Bacteria that convert the nitrates in soil or water to gaseous nitrogen and release it back into the atmosphere
Denitrification: chiefly of bacteria) remove the nitrates or nitrites from (soil, air, or water) by chemical reduction.
Industrial fixation:
o The phosphorus cycle circulates a limited nutrient
Phosphorus cycle: A major nutrient cycle consisting of the routes that phosphorus atoms take through the nested networks of environmental systems.
o Tackling nutrient enrichment requires diverse approaches
Reducing fertilizer use on farms and lawns and timing its application to reduce water runoff
Planting and maintaining vegetation "buffers" around streams to trap nutrient and sediment runoff
Using natural and constructed wetlands to filter storm water and farm runoff
Improving tech in sewage treatment plants to enhance nitrogen and phosphorus capture
Upgrading storm water systems to capture runoff from roads and parking lots
Reducing fossil fuel combustion to minimize atmospheric inputs of nitrogen to waterways
o A systemic approach to restoration of hope for Chesapeake Bay
Complex Systems
Why are environmental issues often difficult to explain and to solve?

How does science study complexity?
Outline
What are systems?
Storage and flows
Properties and behaviors
Relationships between parts of a system
How can we study systems?
Why are systems difficult to understand and predict?
What are Systems?
Collection of parts
Parts
Linkages
Interact in an organized way
Behave in regular, recognizable patterns...
...or chaotic patterns
Random versus Predictable
Types of Flow
Spontaneous Flow
From high concentration to low
Energy dissipated
Non-Spontaneous Flow
From low concentration to high
Requires energy input
System Properties
Stability
Resistance
Resilience
Complexity
Homeostasis
The ability of a system to maintain it's behavior when disturbed
Measured by constancy in value of a certain storage or flow (set point)



Demonstration
Tennis balls and kitchen hardware
Complexity
Parts can have either positive or negative effects on other components


Complexity
Parts can have either positive or negative effects on other components
Effects can be linear or non-linear
Parts can be connected in reticulated patterns
Feedback Loops
A negative feedback loop in which output of one type acts as input that moves the system in the opposite direction. The input and output essentially neutralize each other's effects, stabilizing the system. Blood sugar and insulin



Homeostatic something...
The ability of a biological system to maintain its behavior when disturbed
Measured by constancy in value of a certain storage of flow (set point)
Analogous to a room's thermostat
Negative feedback describes many homeostatic mechanisms in organisms
Complexity
Parts can have either positive or negative effects on other components
Effects can be linear or non-linear
Parts can be connected in reticulated patterns
Feedback loops
Systems have multiple storages and flows
Hierarchies and connected subsystems

Approaches to Science Inquiry
Reductionist Approach
Premise: break it into its parts and study parts separately.
Goal: to reveal cause-effect relationships
Key Tools: controlled experiments with dependent and independent variables

Approaches to Science Inquiry
General Systems Theory
Premise: patterns and connections are key features of interest
Goal: reveal relationships, structures, and interdependence
Key Tools: models of natural phenomena
Simulation Models
Mathematical representations providing a simplified version of reality
How to?
Choose which storages and flows to include
Quantify the nature (+ or -) and the strength (+ or +) of the relationships
Calibrate or validate the model using data (real-world observations)
Scenario Analysis ("What if?")

Why are Systems Difficult to Understand and Predict?
Complexity
Impacts stability, resistance, and resilience
Prevents intuitive understanding
Time lags
Time lag refers to the period that lapses between a cause and an effect;Long lag times make it difficult to establish cause and effect; Long lag times also diminish effectiveness of environmental policy
Distance effects
Distance refers to the separation in space between a cause and an effect. Smoke stacks and acid rain
Hierarchies
Subsystems
Connections between systems
Why are Systems Difficult to Understand and Predict?
Non-linear functions
Threshold effects
Chaos theory
Variability in parameter values
Difficulty in estimation
Prediction of a range of outcomes
Stochasticity
Shit happens
• Evolution: The Source of Earth's Biodiversity
o Natural Selection Shapes Organisms
Natural selection: The process by which traits that enhance survival and reproduction are passed on more frequently to future generations of organisms than traits that do not, thus altering the genetic makeup of populations through time. Natural selection acts on genetic variation and is a primary driver of evolution.
Adaption: (1) The process by which traits that lead to increased reproductive success in a given environment evolve in a population through natural selection. (2) See adaptive trait.
o Selection acts on genetic variation
Convergent evolution: the evolutionary process by which very unrelated species acquire similar traits as they adapt to selective pressures from similar environments
o Evidence of Selection is all around us
Charles Darwin: English naturalist who proposed the concept of natural selection as a mechanism for evolutionand as a way to explain the great variety of living things. Compare Wallace, Alfred Russel.
Alfred Russel Wallace: English naturalist who proposed, independently of Charles Darwin, the concept of natural selection as a mechanism for evolution and as a way to explain the great variety of living things.
Artificial selection: Natural selection conducted under human direction. Examples include the selective breeding of crop plants, pets, and livestock.
o Understanding Evolution is Vital for Modern Society
o Evolution Generates Biodiversity
Biological diversity/biodiversity: The variety of life across all levels of biological organization, including the diversity of species, their genes, their populations, and their communities.
o Speciation Produces New Types of Organisms
Speciation: The process by which new species are generated.
o We can Infer the History of Life's diversification
Phylogenetic trees: A treelike diagram that represents the history of divergence of species or other taxonomic groups of organisms.
o Fossils Reveal Life's History
Fossil: The remains, impression, or trace of an animal or plant of past geological ages that has been preserved in rock or sediments.
Extinction: The disappearance of an entire species from Earth. Compare extirpation.
o Some species are especially vulnerable to extinction
o Earth has seen episodes of mass extinction
Mass extinction events: The extinction of a large proportion of the world's species in a very short time period due to some extreme and rapid change or catastrophic event. Earth has seen five mass extinction events in the past half-billion years.
o The sixth mass extinction is upon us
• Ecology and the Organism
Ecology: The science that deals with the distribution and abundance of organisms, the interactions among them, and the interactions between organisms and their abiotic environments.
o We study ecology at several levels
Biosphere: The sum total of all the planet's living organisms and the abiotic portions of the environment with which they interact.
Ecologist: an expert in or student of ecology:
Population ecology: The study of the quantitative dynamics of population change and the factors that affect the distribution and abundance of members of a population
Community: In ecology, an assemblage of populations of organisms that live in the same place at the same time.
Community ecology: The scientific study of patterns of species diversity and interactions among species, from one-to-one interactions to complex interrelationships involving entire communities
Ecosystems: All organisms and nonliving entities that occur and interact in a particular area at the same time.
Ecology: The science that deals with the distribution and abundance of organisms, the interactions among them, and the interactions between organisms and their abiotic environments.
Landscape ecology: The study of how landscape structure affects the abundance, distribution, and interaction of organisms. This approach to the study of organisms and their environments at the landscape scale focuses on broad geographical areas that include multiple ecosystems.
o Habitat, niche, and specialization are key concepts in ecology
Habitat: The specific environment in which an organism lives, including both biotic and abiotic factors.
Habitat use: The process by which organisms use habitats from among the range of options they encounter.
Habitat selection: The process by which organisms select habitats from among the range of options they encounter.
Niche: The functional role of a species in a community.
Specialist: a person who concentrates primarily on a particular subject or activity; a person highly skilled in a specific and restricted field.
Generalist: a person competent in several different fields or activities:

• Population Ecology
o Populations show features that help predict their dynamics
Population size
• Population size: The number of individual organisms present at a given time in a population.
Population density
• Population density: The number of individuals within a population per unit area. Compare population size
Population distribution
• Population distribution:
The spatial arrangement of organisms within a particular area.
Sex ratio
• Sex ratio: The proportion of males to females in a population.
Age structure
• Age structure:
o We can Measure Population Growth
Demographer: A social science that applies the principles of population ecology to the study of statistical change in human populations.

Population change is determined by four factors:
• Natality: births within the population
• Mortality: deaths within the population
• Immigration: arrival of individuals from outside the population
• Emigration: departure of individuals from the population
• Rate of natural increase: The rate of change in a population's size per unit time (generally expressed in percent per year), taking into accounts births, deaths, immigration, and emigration. Compare rate of natural increase.
• Population growth rate: The rate of change in a population's size per unit time (generally expressed in percent per year), taking into accounts births, deaths, immigration, and emigration. Compare rate of natural increase.
o Unregulated populations increase by exponential growth
Exponential growth: The increase of a population (or of anything) by a fixed percentage each year.
o Limiting Factors Restrain Growth
Limiting factors: A physical, chemical, or biological characteristic of the environment that restrains population growth.
Carrying capacity: The maximum population size that a given environment can sustain.
Logistic growth: A plot that shows how the initial exponential growth of a population is slowed and finally brought to a standstill by limiting factors.
Density-dependent: The condition of a limiting factor whose effects on a population increase or decrease depending on the population density. Compare density-independent factor.
Density-independent: The condition of a limiting factor whose effects on a population are constant regardless of population density. Compare density-dependent factor.
o Carrying capacities can change
• Conserving Biodiversity
o Innovative solutions are working
o Climate change poses an extra challenge


Chapter 4: Species Interaction

• Species Interactions
o Competition Can Occur When Resources are limited
Competition: relationship in which multiple organisms seek the same limited resource
Resource partitioning: the process by which species adapt to competition by evolving to use slightly different resources, thus minimizing interference with one another
o Predators Kill and Consume Prey
Predation: The process in which one species (the predator) hunts, tracks, captures, and ultimately kills its prey.
o Parasites Exploit Living Hosts
Parasitism: A relationship in which one organism, the parasite, depends on another, the host, for nourishment or some other benefit while simultaneously doing the host harm. Compare mutualism.
o Herbivores Exploit Plants
Herbivory: the consumption of plants by animals.
o Mutualists Help One Another
Mutualism: A relationship in which all participating organisms benefit from their interaction. Compare parasitism.
Symbiosis: a relationship between different species of organisms that live in close physical proximity. People often use the term "symbiosis" where referring to a mutualism, but symbiotic relationships can be either parasitic or mutualistic
Pollination: A plant-animal interaction in which one organism (for example, a bee or a hummingbird) transfers pollen (containing male sex cells) from flower to flower, fertilizing ovaries (containing female sex cells) that grow into fruits with seeds.
• Ecological Communities
Community: In ecology, an assemblage of populations of organisms that live in the same place at the same time.
o Energy passes among trophic level
Trophic level: Rank in the feeding hierarchy of a food chain. Organisms at higher trophic levels consume those at lower trophic levels.
• Producers (autotroph): an organism that uses energy from sunlight to produce its own food. Includes green plants, algae, and cyanobacteria
• Consumers:
• Detritivores and Decomposers: an organism such as a millipede or soil insect that scavenges the waste products or dead bodies of other community members...........organism, such as fungus or bacterium, that breaks down leaf litter and other nonliving matter into simple constituents that can be taken up and used by plants
o Energy, Numbers, and Biomass Decrease at Higher Trophic Levels
Biomass: (1) In ecology, organic material that makes up living organisms; the collective mass of living matter in a given place and time. (2) In energy, organic material derived from living or recently living organisms, containing chemical energy that originated with photosynthesis.
o Food Webs Show Feeding Relationships and Energy Flow
Food chain: A linear series of feeding relationships. As organisms feed on one another, energy is transferred from lower to higher trophic levels. Compare food web.
Food web: A visual representation of feeding interactions within an ecological community that shows an array of relationships between organisms at different trophic levels. Compare food chain.
o Some Organisms play Outsized Roles
Keystone species: A species that has an especially far-reaching effect on a community.
Trophic cascade: A series of changes in the population sizes of organisms at different trophic levels in a food chain, occurring when predators at high trophic levels indirectly promote populations of organisms at low trophic levels by keeping species at intermediate trophic levels in check. Trophic cascades may become apparent when a top predator is eliminated from a system.
o Communities Respond to Disturbance in Various Ways
Disturbances: An event that affects environmental conditions rapidly and drastically, resulting in changes to the community and ecosystem. Disturbance can be natural or can be caused by people
Resistance: The ability of an ecological community to remain stable in the presence of a disturbance. Compare resilience.
Resilience: The ability of an ecological community to change in response to disturbance but later return to its original state. Compare resistance.
o Succession Follows Severe Disturbance
Succession: A stereotypical series of changes in the composition and structure of an ecological community through time. See primary succession; secondary succession.
Primary Succession: A stereotypical series of changes as an ecological community develops over time, beginning with a lifeless substrate. In terrestrial systems, primary succession begins when a bare expanse of rock, sand, or sediment becomes newly exposed to the atmosphere and pioneer species arrive. Compare secondary succession.
Secondary succession: A stereotypical series of changes as an ecological community develops over time, beginning when some event disrupts or dramatically alters an existing community. Compare primary succession
Pioneer species: A species that arrives earliest, beginning the ecological process of succession in a terrestrial or aquatic community.
o Communities may undergo shifts
Phase shift/ regime shift: A fundamental shift in the overall character of an ecological community, generally occurring after some extreme disturbance, and after which the community may not return to its original state. Also known as a regime shift.
Novel communities/ no-analog communities: An ecological community composed of a novel mixture of organisms, with no current analog or historical precedent.
o Invasive Species Pose Threats to Communities Stability
Introduced species: Species introduced by human beings from one place to another (whether intentionally or by accident). A minority of introduced species may become invasive species.
Invasive species: A species that spreads widely and rapidly becomes dominant in a community, interfering with the community's normal functioning.
o We Can Respond to Invasive Species with Control, Eradication, or Prevention
o Altered Communities can be Restored
Restoration ecology: The study of the historical conditions of ecological communities as they existed before humans altered them. Principles of restoration ecology are applied in the practice of ecological restoration.
Ecological restoration: Efforts to reverse the effects of human disruption of ecological systems and to restore communities to their condition before the disruption. The practice that applies principles of restoration ecology.
• Earth's Biomes
Biomes: A major regional complex of similar plant communities; a large ecological unit defined by its dominant plant type and vegetation structure.
o Climate helps determine biomes
Climate diagrams/climatographs: A visual representation of a region's average monthly temperature and precipitation. Also known as a climatograph.
o Aquatic and Coastal Systems Resemble Biomes
o We can Divide the World into 10 Terrestrial Biomes
Temperate Deciduous Forest: A biome consisting of midlatitude forests characterized by broad-leafed trees that lose their leaves each fall and remain dormant during winter. These forests occur in areas where precipitation is spread relatively evenly throughout the year.
Temperate Grasslands: A biome whose vegetation is dominated by grasses and features more extreme temperature differences between winter and summer and less precipitation than temperate deciduous forests. Also known as steppe, prairie.
Temperate Rainforest: A biome consisting of tall coniferous trees, cooler and less species-rich than tropical rainforest and milder and wetter than temperate deciduous forest.
Tropical Rainforest: A biome characterized by year-round rain and uniformly warm temperatures. Tropical rainforests have dark, damp interiors; lush vegetation; and highly diverse biotic communities.
Tropical Dry Forest/Tropical Deciduous Forest: A biome that consists of deciduous trees and occurs at tropical and subtropical latitudes where wet and dry seasons each span about half the year. Also known as tropical deciduous forest.
Savanna: A biome characterized by grassland interspersed with clusters of acacias and other trees in dry tropical regions.
Desert: The driest biome on Earth, with annual precipitation of less than 25 cm. Because deserts have relatively little vegetation to insulate them from temperature extremes, sunlight readily heats them in the daytime, but daytime heat is quickly lost at night, so temperatures vary widely.
Tundra: A biome that is nearly as dry as desert but is located at very high latitudes. Extremely cold winters with little daylight and moderately cool summers with lengthy days characterize this landscape of lichens and low, scrubby vegetation.
Boreal Forest/Taiga: A biome of northern coniferous forest. Also known as taiga, boreal forest consists of a limited number of species of evergreen trees, such as black spruce, that dominate large regions of forests interspersed with occasional bogs and lakes.
Chaparral: A biome consisting mostly of densely thicketed evergreen shrubs occurring in limited small patches. Its "Mediterranean" climate of mild, wet winters and warm, dry summers is induced by oceanic influences.
Chapter 3: Evolution, Ecology, and Biodiversity
Life: an evolutionary play on an ecological stage
The phylogeny (tree!) of life
Population ecology
The Play: Evolution
Evolution and natural selection
Evolution = genetic (DNA) change in a population of organisms across generations
Doesn't happen to individual organisms; it happens in groups
Generations can be hours, months, years, etc

Natural selection = process by which traits that provide an advantage in survival or reproduction are passed on to future generations
This alters the genetic makeup of populations over time
Mechanisms of evolution
Gene flow: several individuals are entering a new population
Natural selection: resembling other things for protection; attraction; special features/characteristics
Genetic drift: some individuals reproduce by chance while others do not
Natural selection shapes diversity
Charles Darwin and Alfred Russell Wallace independently proposed natural selection to explain the variety of living things.
A trait that promotes success in a given habitat is called an adaptive trait or an adaptation.
Organisms therefore differ in relative fitness
Misconception: evolution always favors complexity/increasing size/etc...
A trait that is adaptive in one location or season may prove maladaptive in another...
Evolution can favor simplicity, or different traits in different settings
Mutation and genetic variation
For a trait to be heritable, genes in an organism's DNA must code for the trait.
Mutations are accidental changes in DNA.
Mutations that are not lethal provide the genetic variation on which natural selection acts.
Misconception: Organisms do not 'mutate' in a direction of greater fitness
Mutations provide the raw material for evolutionary change.
Putting it together
The Ecological Theater and the Evolutionary Play
G. Evelyn Hutchinson, 1965
'Nothing in Biology Makes Sense Except in the Light of Evolution'
Theodosius Dobzhansky, 1973
Habitat and niche
Habitat (where an organism lives) = the specific environment where an organism lives
including living and nonliving elements: rocks, soil, plants, etc...
Niche (what an organism does) = an organism's functional role (feeding, flow of energy and matter, interactions with other organisms, etc.)
Specialists = organisms with narrow breadth and thus very specific requirements
Pandas can only eat bamboo and can only live in areas with bamboo
Endangered species tend to be more likely to be specialists
Generalists = have much broader niches
Humans because we can live almost anywhere and eat almost anything
Central Case: Striking Gold in a Costa Rican Cloud Forest
The golden toad of Monteverde
Discovered 1964
Disappeared 25 years later.

Warming and drying of the forest
was likely responsible
Golden toads of Monteverde

Species and Speciation
A species is a particular type of organism;
a population or group of populations whose members share certain characteristics
and can freely interbreed with one another and produce fertile offspring.
Speciation: The process by which new species come into being
It is an evolutionary process that has given Earth its current species richness—more than 1.5 million described species
Allopatric speciation
Start with a single interbreeding population...
...then divided by a barrier...
Allopatric speciation
Allopatric speciation
...The two populations adapt independently, diverging in their traits...
...Then populations reunited when barrier removed.
Phylogenetic trees
Life's diversification results from countless speciation events over vast spans of time.
Evolutionary history of divergence is illustrated with phylogenetic trees.
Similar to family genealogies, these show relationships among organisms.
The Tree of Life
By studying extant species or their genes we can infer relationships among major groups of living organisms
There has been a single origin of life on earth-one lineage with many branches
Phylogenetic trees
We can zoom in on any group to view a more detailed tree for those organisms

Phylogenetic trees
Zooming in on the vertebrates...

...and so on
The Stage: Ecology
Life's hierarchy
Ecologists deal with levels of organization from organisms on up
They attempt to describe the distribution and abundance of organisms
Population ecology
Population ecologists investigate changes in population size (N) over time
Several attributes help predict population dynamics (dN/dt):
Current population size
Population density
Population distribution
Sex ratio
Age structure
Birth and death rates
Population growth
Populations may grow, shrink, or remain stable, depending on:
(crude birth rate + immigration rate) -
(crude death rate + emigration rate)
= dN/dt
Change over time
How quickly are populations changing
Age structure
Exponential growth
Some populations increase by exponential growth:

Growth by a fixed percentage, rather than a fixed amount.

Similar to growth of money in a savings account
Exponential growth
Exponential growth produces J-shaped curves of population size vs. time

Nt = N0ert
or
dN/dt = rN
Limits on growth?
The Elephant Problem - Darwin, 1859
http://www.athro.com/evo/elframe.html

Limiting factors restrain exponential growth, slowing the growth rate down.
Population levels off at a carrying capacity
K = the maximum population size of a given species an environment can sustain
Population growth rate (dN/dt) depends on N
Logistic growth
Density dependence limits growth
The condition of a limiting factor whose effects on a population increase or decrease depending on the population density. Compare density-independent factor.
Often, survival or reproduction lessens as populations become more dense.
'density-dependent factors' (disease, predation, etc.)
key is these factors link b and/or d to N

Other factors affect b, d regardless of density
and are 'density-independent factors'
(e.g., catastrophic weather events).
Logistic growth
Population oscillations
Dampened oscillations
Population growth: Crashes

Reproductive strategies
Species differ in strategies for producing young.
Some produce lots of young (insects, fish, frogs, plants) and have high biotic potential.

Others, such as mammals and birds, produce few young...
...but give them more care, resulting in better survival.
r- vs. K-selected species
r-selected species
Many offspring
Fast growing
No parental care
K-selected species
Few offspring
Slow growing
Parental care
Terms come from
r = intrinsic rate of population increase. (Populations can grow fast, have high r.)
Exponential growth


K = carrying capacity.
(Populations stabilize near K.)
• Species Interactions
o Competition Can Occur When Resources are limited
Competition: relationship in which multiple organisms seek the same limited resource
Resource partitioning: the process by which species adapt to competition by evolving to use slightly different resources, thus minimizing interference with one another
o Predators Kill and Consume Prey
Predation: The process in which one species (the predator) hunts, tracks, captures, and ultimately kills its prey.
o Parasites Exploit Living Hosts
Parasitism: A relationship in which one organism, the parasite, depends on another, the host, for nourishment or some other benefit while simultaneously doing the host harm. Compare mutualism.
o Herbivores Exploit Plants
Herbivory: the consumption of plants by animals.
o Mutualists Help One Another
Mutualism: A relationship in which all participating organisms benefit from their interaction. Compare parasitism.
Symbiosis: a relationship between different species of organisms that live in close physical proximity. People often use the term "symbiosis" where referring to a mutualism, but symbiotic relationships can be either parasitic or mutualistic
Pollination: A plant-animal interaction in which one organism (for example, a bee or a hummingbird) transfers pollen (containing male sex cells) from flower to flower, fertilizing ovaries (containing female sex cells) that grow into fruits with seeds.
• Ecological Communities
Community: In ecology, an assemblage of populations of organisms that live in the same place at the same time.
o Energy passes among trophic level
Trophic level: Rank in the feeding hierarchy of a food chain. Organisms at higher trophic levels consume those at lower trophic levels.
• Producers (autotroph): an organism that uses energy from sunlight to produce its own food. Includes green plants, algae, and cyanobacteria
• Consumers:
• Detritivores and Decomposers: an organism such as a millipede or soil insect that scavenges the waste products or dead bodies of other community members...........organism, such as fungus or bacterium, that breaks down leaf litter and other nonliving matter into simple constituents that can be taken up and used by plants
o Energy, Numbers, and Biomass Decrease at Higher Trophic Levels
Biomass: (1) In ecology, organic material that makes up living organisms; the collective mass of living matter in a given place and time. (2) In energy, organic material derived from living or recently living organisms, containing chemical energy that originated with photosynthesis.
o Food Webs Show Feeding Relationships and Energy Flow
Food chain: A linear series of feeding relationships. As organisms feed on one another, energy is transferred from lower to higher trophic levels. Compare food web.
Food web: A visual representation of feeding interactions within an ecological community that shows an array of relationships between organisms at different trophic levels. Compare food chain.
o Some Organisms play Outsized Roles
Keystone species: A species that has an especially far-reaching effect on a community.
Trophic cascade: A series of changes in the population sizes of organisms at different trophic levels in a food chain, occurring when predators at high trophic levels indirectly promote populations of organisms at low trophic levels by keeping species at intermediate trophic levels in check. Trophic cascades may become apparent when a top predator is eliminated from a system.
o Communities Respond to Disturbance in Various Ways
Disturbances: An event that affects environmental conditions rapidly and drastically, resulting in changes to the community and ecosystem. Disturbance can be natural or can be caused by people
Resistance: The ability of an ecological community to remain stable in the presence of a disturbance. Compare resilience.
Resilience: The ability of an ecological community to change in response to disturbance but later return to its original state. Compare resistance.
o Succession Follows Severe Disturbance
Succession: A stereotypical series of changes in the composition and structure of an ecological community through time. See primary succession; secondary succession.
Primary Succession: A stereotypical series of changes as an ecological community develops over time, beginning with a lifeless substrate. In terrestrial systems, primary succession begins when a bare expanse of rock, sand, or sediment becomes newly exposed to the atmosphere and pioneer species arrive. Compare secondary succession.
Secondary succession: A stereotypical series of changes as an ecological community develops over time, beginning when some event disrupts or dramatically alters an existing community. Compare primary succession
Pioneer species: A species that arrives earliest, beginning the ecological process of succession in a terrestrial or aquatic community.
o Communities may undergo shifts
Phase shift/ regime shift: A fundamental shift in the overall character of an ecological community, generally occurring after some extreme disturbance, and after which the community may not return to its original state. Also known as a regime shift.
Novel communities/ no-analog communities: An ecological community composed of a novel mixture of organisms, with no current analog or historical precedent.
o Invasive Species Pose Threats to Communities Stability
Introduced species: Species introduced by human beings from one place to another (whether intentionally or by accident). A minority of introduced species may become invasive species.
Invasive species: A species that spreads widely and rapidly becomes dominant in a community, interfering with the community's normal functioning.
o We Can Respond to Invasive Species with Control, Eradication, or Prevention
o Altered Communities can be Restored
Restoration ecology: The study of the historical conditions of ecological communities as they existed before humans altered them. Principles of restoration ecology are applied in the practice of ecological restoration.
Ecological restoration: Efforts to reverse the effects of human disruption of ecological systems and to restore communities to their condition before the disruption. The practice that applies principles of restoration ecology.
• Earth's Biomes
Biomes: A major regional complex of similar plant communities; a large ecological unit defined by its dominant plant type and vegetation structure.
o Climate helps determine biomes
Climate diagrams/climatographs: A visual representation of a region's average monthly temperature and precipitation. Also known as a climatograph.
o Aquatic and Coastal Systems Resemble Biomes
o We can Divide the World into 10 Terrestrial Biomes
Temperate Deciduous Forest: A biome consisting of midlatitude forests characterized by broad-leafed trees that lose their leaves each fall and remain dormant during winter. These forests occur in areas where precipitation is spread relatively evenly throughout the year.
Temperate Grasslands: A biome whose vegetation is dominated by grasses and features more extreme temperature differences between winter and summer and less precipitation than temperate deciduous forests. Also known as steppe, prairie.
Temperate Rainforest: A biome consisting of tall coniferous trees, cooler and less species-rich than tropical rainforest and milder and wetter than temperate deciduous forest.
Tropical Rainforest: A biome characterized by year-round rain and uniformly warm temperatures. Tropical rainforests have dark, damp interiors; lush vegetation; and highly diverse biotic communities.
Tropical Dry Forest/Tropical Deciduous Forest: A biome that consists of deciduous trees and occurs at tropical and subtropical latitudes where wet and dry seasons each span about half the year. Also known as tropical deciduous forest.
Savanna: A biome characterized by grassland interspersed with clusters of acacias and other trees in dry tropical regions.
Desert: The driest biome on Earth, with annual precipitation of less than 25 cm. Because deserts have relatively little vegetation to insulate them from temperature extremes, sunlight readily heats them in the daytime, but daytime heat is quickly lost at night, so temperatures vary widely.
Tundra: A biome that is nearly as dry as desert but is located at very high latitudes. Extremely cold winters with little daylight and moderately cool summers with lengthy days characterize this landscape of lichens and low, scrubby vegetation.
Boreal Forest/Taiga: A biome of northern coniferous forest. Also known as taiga, boreal forest consists of a limited number of species of evergreen trees, such as black spruce, that dominate large regions of forests interspersed with occasional bogs and lakes.
Chaparral: A biome consisting mostly of densely thicketed evergreen shrubs occurring in limited small patches. Its "Mediterranean" climate of mild, wet winters and warm, dry summers is induced by oceanic influences.
Chapter 4: Larger-scale ecology
Species interactions
Communities
Biomes
Energy flows
Biomass Pyramid
Species interactions
Competition
Food Webs
Food webs give a more complete description of natural systems than food chains
Food webs are conceptual representations of feeding relationships in a community.
Keystone Species
Are some species in a community more 'important' than others?
Keystone species: A species that has an especially far-reaching effect on a community.
Dominant species
The kelp is the DS
In this case the sea otter is the KS b/c SO eat urchins who eat kelp
Kelp forest (with otters)
Kelp forest (w/o otters)
Keystone vs. Dominant Species
Disturbance and Succession
Resistance?
Resilience?
Both?...or Neither?
Primary succession: A stereotypical series of changes as an ecological community develops over time, beginning with a lifeless substrate. In terrestrial systems, primary succession begins when a bare expanse of rock, sand, or sediment becomes newly exposed to the atmosphere and pioneer species arrive. Compare secondary succession.
Are some species in a community more 'important' than others?
Keystone species
Dominant species
Pioneer species: A species that arrives earliest, beginning the ecological process of succession in a terrestrial or aquatic community.
Secondary Succession
Resistance and Resilience
Resistance
Community remains stable despite disturbance

Resilience
Community returns quickly to original state after disturbance
Invasive species
Are some species in a community more 'important' than others?
Keystone species
Dominant species
Pioneer species
Invasive species: A species that spreads widely and rapidly becomes dominant in a community, interfering with the community's normal functioning.
Keystone v. dominate example
A keystone is the wedge-shaped stone at the top of an arch that holds its structure together (a). A keystone species, such as the sea otter, is one that exerts great influence on a community's composition and structure (b). Sea otters consume sea urchins, which eat kelp in marine nearshore environments of the Pacific. hen otters are present, they keep urchin numbers down, allowing lush underwater forests of kelp to grow and provide habitat for many other species. hen otters are absent, urchin populations increase and devour the kelp, destroying habitat and depressing species diversity.

Intake Pipes
Zebra mussels in the Hudson
Filter-feeding increased 30 x
Effects on invertebrates:
Phytoplankton 80%
Small zooplankton 76%
Large zooplankton 52%
Benthic invertebrates 10%
What about vertebrates?
Fieldwork!


Hudson river fish community
Response to invasive species?
Control
Chemical
Natural predators
Eradication
Removal
Prevention
Ballast water regulations
Restoration Ecology
Human response to human disturbance
Rebuild wetlands (ex: Florida everglades)
Restore forests (ex: change logging practices)
Restore grasslands (ex: controlled burns, remove livestock)
Are all invasive species bad?
Although mustangs are not native to the U.S., they exist in several western states, on federally owned land. As an introduced species, what should be done with them?
As an exotic species, they should immediately be removed and adopted.
As an exotic species, they should immediately be removed and killed.
Although they are an exotic species, they are part of our heritage, and should be allowed to stay.
They have been here so long, we should just leave them alone.
Many countries eat horse flesh, so we should round them up and export them to horse-eating countries.
Sustainable Solutions
Biomes
Recognized by Vegetation
Defined by Average T and Ppt
T and Ppt = Biome in a Location
Terrestrial Biomes
Temperate deciduous forest
Temperate grassland
Temperate rainforest
Tropical Rainforest
Tropical dry forest
Savanna
Desert
Tundra
Boreal forest
Chaparral
• Economics and the Environment
Economy: A social system that converts resources into goods and services.
Economics: The study of how we decide to use scarce resources to satisfy demand for goods and services.
o Economies rely on goods and services from the environment
o Economic theory moved from "invisible hand" to supply and demand
Classical economics: Founded by Adam Smith, the study of the behavior of buyers and sellers in a capitalist market economy. Holds that individuals acting in their own self-interest may benefit society, provided that their behavior is constrained by the rule of law and by private property rights and operates within competitive markets. See also neoclassical economics.
Neoclassical economies: A mainstream economic school of thought that explains market prices in terms of consumer preferences for units of particular commodities and that uses cost-benefit analysis. Compare ecological economics; environmental economics.
Cost-benefit analysis: A method commonly used by neoclassical economists, in which estimated costs for a proposed action are totaled and then compared to the sum of benefits estimated to result from the action.
o Neoclassical economics has environmental consequences
Replacing resources
External Costs
• External cost: A cost borne by someone not involved in an economic transaction. Examples include harm to citizens from water pollution or air pollution discharged by nearby factories.
o Health problems
o Declines in resources
o Aesthetic damage
o Declining real estate values
Discounting
Growth
• Economic growth: An increase in an economy's activity—that is, an increase in the production and consumption of goods and services.
o How sustainable is economic growth?
Environmental economies: A developing school of economics that modifies the principles of neoclassical economics to address environmental challenges. Most environmental economists believe that we can attain sustainability within our current economic systems. Compare ecological economics; neoclassical economics.
Ecological economics: A developing school of economics that applies the principles of ecology and systems thinking to the description and analysis of economies. Compare environmental economics; neoclassical economics.
Steady-state economies: An economy that does not grow or shrink but remains stable.
o We can assign monetary value to ecosystem good and services
Nonmarket value: A value that is not usually included in the price of a good or service.
o We can measure progress with full cost accounting
Gross Domestic Product (GDP): The total monetary value of final goods and services produced in a country each year. GDP sums all economic activity, whether good or bad. Compare Genuine Progress Indicator (GPI).
Genuine Progress Indicator: An economic indicator that attempts to differentiate between desirable and undesirable economic activity. The GPI accounts for benefits such as volunteerism and for costs such as environmental degradation and social upheaval. Compare Gross Domestic Product (GDP).
Full cost accounting/ true cost accounting: An accounting approach that attempts to summarize all costs and benefits by assigning monetary values to entities without market prices and then generally subtracting costs from benefits. Examples include the Genuine Progress Indicator, the Happy Planet Index, and others. Also called true cost accounting.
o Markets Can Fail
Market failure: The failure of markets to take into account the environment's positive effects on economies (for example, ecosystem services) or to reflect the negative effects of economic activity on the environment and thereby on people (external costs).
• Environmental Policy: An Overview
Policy: A rule or guideline that directs individual, organizational, or societal behavior.
Public Policy: Policy made by governments, including those at the local, state, federal, and international levels; it consists of legislation, regulations, orders, incentives, and practices intended to advance societal welfare. See also environmental policy.
Environmental policy: Public policy that pertains to human interactions with the environment. It generally aims to regulate resource use or reduce pollution to promote human welfare and/or protect natural systems.
o Environmental policy addresses issues of fairness and resource use
Why governments intervene:
• To provide social services
• To provide a safety net
• To eliminate unfair advantages held by single buyers or sellers
• To manage publicly held resources
• To minimize pollution and other threats to health and quality of life ((end))
• Tragedy of the commons
o Tragedy of the commons: The process by which publicly accessible resources open to unregulated use tend to become damaged and depleted through overuse. Coined by Garrett Hardin and widely applicable to resource issues.
• Free riders
o Free riders: A party that fails to invest in controlling pollution or carrying out other environmentally responsible activities and instead relies on the efforts of other parties to do so. For example, a factory that fails to control its emissions gets a "free ride" on the efforts of other factories that do make the sacrifices necessary to reduce emissions.
• External cost
o Various factors can obstruct environmental policy
o Science informs policy but it sometimes disregarded
• US Environmental Law and Policy
o The federal government's three branches shape policy
Legislation: Statutory law.
Regulation: A specific rule issued by an administrative agency, based on the more broadly written statutory law passed by Congress and enacted by the president.
o Early US environmental policy promoted development
First Period: 1780s- late 1800s: General Land Ordinances of 1785 and 1787
Basically took land from Native Americans
o The Second wave of US environmental policy encouraged conservation
In the late 1800s
Aimed to alleviate some of the environmental impacts of westward expansion
o The third wave responded to pollution
20th century
driven my technology
o Passage of NERPA and creation of EPA were milestones
National Environmental Policy Act (NERPA): A U.S. law enacted on January 1, 1970, that created an agency called the Council on Environmental Quality and required that an environmental impact statement be prepared for any major federal action.
Environmental impact statement (EIS): A report of results from detailed studies that assess the potential effects on the environment that would likely result from development projects or other actions undertaken by the government.
Environmental Protection Agency (EPA): An administrative agency charged with conducting and evaluating research, monitoring environmental quality, setting standards, enforcing those standards, assisting the states in meeting standards and goals for environmental protection, and educating the public.
o Social context for policy evolves
o Environmental policy advances today on the international stage
• International Environmental Policy
o Globalization makes international institutions vital
Globalization: The process by which the world's societies have become more interconnected, linked by trade and communication technologies in countless ways.
o International law includes customary law and conventional law
Customary law: International law that arises from long-standing practices, or customs, held in common by most cultures. Compare conventional law.
Conventional law: International law that arises from conventions, or treaties, that nations agree to enter into. Compare customary law.
North American Free Trade Agreement (NAFTA): A 1994 treaty among Canada, Mexico, and the United States that reduced or eliminated barriers to trade (such as tariffs) among these nations. Side agreements were negotiated to minimize the degree to which protections for workers and the environment were undermined.
o Several organizations shape international environment policy
The United Nations
• The United Nations: Organization founded in 1945 to promote international peace and to cooperate in solving international economic, social, cultural, and humanitarian problems.
The World Bank
• The World Bank: Institution founded in 1944 that serves as one of the globe's largest sources of funding for economic development, including such major projects as dams, irrigation infrastructure, and other undertakings.
The World Trade Organization
• The World Trade Organization: Organization based in Geneva, Switzerland, that represents multinational corporations and promotes free trade by reducing obstacles to international commerce and enforcing fairness among nations in trading practices.
Nongovernmental organizations
• Nongovernmental organizations: An organization not affiliated with any national government, and frequently international in scope, that pursues a particular mission or advocates for a particular cause.
• Approaches to Environmental policy
o Policy can follow three approaches
Lawsuits of the court
Command-and-control policy
• Command-and-control policy: A top-down approach to policy, in which a legislative body or a regulating agency sets rules, standards, or limits and threatens punishment for violations of those limits.
Economic policy tools
o Green taxes discourage undesirable activities
Green taxes: A levy on environmentally harmful activities and products aimed at providing a market-based incentive to correct for market failure. Compare subsidy.
Polluter-pays principle: Principle specifying that the party responsible for producing pollution should pay the costs of cleaning up the pollution or mitigating its impacts.
o Subsidies promote certain activities
Subsidy: A government grant of money or resources to a private entity, intended to support and promote an industry or activity.
o Eco labeling empowers consumers
Ecolabeling: The practice of designating on a product's label how the product was grown, harvested, or manufactured, so that consumers are aware of the processes involved and can judge which brands use more sustainable processes.
o Emissions trading can produce cost-effective results
Emissions trading: The practice of buying and selling government-issued marketable emissions permits to conduct environmentally harmful activities. Under a cap-and-trade system, the government determines an acceptable level of pollution and then issues permits to pollute. A company receives credit for amounts it does not emit and can then sell this credit to other companies. Compare cap-and-trade.
Cap-and-trade: An emissions trading system in which government determines an acceptable level of pollution and then issues polluting parties permits to pollute. A company receives credit for amounts it does not emit and can then sell this credit to other companies.
o Market incentives are diverse at the local level
• Sustainable Development
Sustainable development: Development that satisfies our current needs without compromising the future availability of natural capital or our future quality of life.
o Sustainable development involves environmental protection, economic well-being, and social equity
o Sustainable development is global
Human Population
How population size, affluence, and technology determine human impact on the environment
Figure 6.2 Labeled
Human Population Growth
SE 6-4 Human population growth
Is growth really a problem?
NO
People can find or manufacture additional resources to keep pace with population growth.
Nations become stronger as their populations grow.
YES
Not all resources can be replaced.
Even if they could, quality of life suffers.
Nations do not become stronger as their populations grow.
SE 6-4 Human population growth
SE 6-4 Human population growth
SE 6-4 Human population growth
Technology can change K
What is the Human K
Estimates from 2 billion to 1 trillion
high estimate assumes living in floating cities and huge advances in technology

K depends on standard of living
At N = 1 trillion everyone gets 100 sq. meters and 1500 calories per day
'Little r'
Exponential growth is described by the equation
Nt = N0ert

'r' is the natural rate of population change
due to birth ('b') and death ('d') rates per capita
(excludes immigration and emigration)
units of % per year.
Population Growth Rates, 2013
Projected Human N
Activity
Divide into groups and calculate these two projected values:
doubling time of the human population
N of humans in 2050 (in 42 years)
Nt = N0ert
r= 0.75
r=.0075
T=33 yrs
No= 7.5 billion

Nt= (7.5)e^(.0075x33)= 9.6 billion

TFR strongly influences 'r'
Total fertility rate (TFR) = average number of children born per woman during her lifetime

Replacement fertility = the TFR that keeps population size stable
For humans, replacement fertility is about 2.1
Why not 1.0? 2.0?
Total fertility rates
Demography is the study of human population
The study of population size, density, distribution, age structure, sex ratio, and rates of birth, death, immigration, and emigration of people.
Age structure diagrams (often called population pyramids) are visual tools scientist use to illustrate age structure
Demographic transition theory
Demographic transition = model of economic and cultural change
Explains pattern observed in Western nations as they became industrialized
declining death rates,
declining birth rates,
and rising life expectancies
SE 6-12 Demographic transition
SE 6-12 Demographic transition
SE 6-12 Demographic transition
SE 6-12 Demographic transition
Demographic transition theory
Pre-industrial stage: high death rates and high birth rates.
Transitional stage: death rates fall due to rising food production and better medical care
Industrial stage: birth rates fall, as women are employed and as children become less economically useful in an urban setting.
Post-industrial stage: birth and death rates remain low and stable
The "IPAT" model
Shows how Population, Affluence, and Technology interact to create Impact on our environment.
I = P A T
Revisit your global footprint...
Go to www.footprintnetwork.org
Calculate your 'global footprint' based on your lifestyle as before...

Now recalculate assuming the density of your living conditions has doubled.
Is this better? Yes or no, and why, by next class session...
Global Ecological Footprint
Zero Population Growth (ZPG)
Should we set ZPG as a goal for humans?
Can be attained by adjustments in either birth or death rates...
...and we might not like the environmental conditions leading to high death rates?

If so, how do we accomplish this?
Views on population control
Discussion Time!
The best way to reduce growth rate for the human population is
Free access to condoms for males and females
Free access to birth-control pills for females
Free access to abortion
Increased access to education for females
Prohibition of pre- and perinatal healthcare
A strict one-child policy, such as that enacted in the People's Republic of China
A laissez-faire approach, since nature is ultimately self-correcting
HIV and population growth
Southern Africa
Infects 1 in 5
kills babies born to infected moms
orphaned over 14 million children
cut 19 yr from life expectancies
HIV and population growth
Female literacy and TFR
Poverty and TFR
Family planning & contraception
Family planning is a key approach for controlling population growth
Family planning the effort plan the number and spacing of one's children.
Birth control the effort to control the number of children one bears, particularly by reducing the frequency of pregnancy
Contraception the deliberate attempt to prevent pregnancy despite sexual intercourse
Reproductive window the period of a woman's life beginning with sexual maturity and ending with menopause, in which she may become pregnant. Woman can have 25 children within that window
TFR in Bangledesh
What role should the U.S. play?
Funds to support UN programs for family planning has been appropriated by Congress annually for > 20 years

Is this appropriate? Views vary...
http://www.unfpa.org/public/News/pid/1562

Inequality in future growth
Demographic fatigue ='failed states'?
Many governments of developing countries are experiencing demographic fatigue
unable to meet the social, economic, and environmental challenges driven by rapid population growth
Can lead to failed states = social and political chaos that can expand regionally
This raises the question:
Will today's developing countries successfully pass through the demographic transition?
Affluence and the environment
Poverty can lead to environmental degradation...

BUT

wealth and resource consumption can produce even more severe and far-reaching environmental impacts.
Key Points
The human population is larger than at any time in the past.
90% of children born today are likely to live in conditions far less healthy and prosperous than those in the industrialized world.
The rate of growth has decreased nearly everywhere, and some countries are seeing population declines.
Most developed nations are through the demographic transition and could transition to ecologically sustainable economies.
Key Points (cont.)
Many developing nations are making their way through the demographic transition, and equitable treatment is vital to their success.
Women's rights are expanding worldwide, which helps slow population growth.
Contraception is an important tool to reduce TFR
Sustainability demands that we stabilize our population size as part of a sustainable future, a critical insight of I = PAT.
The Production of Food
Malthus' paradox
Subsistence agriculture, the Green Revolution, and more sustainable methods
Food Aid and food trade
Human agriculture
Human agriculture
Thomas Malthus (1798)
What did he get wrong?
Changes in agricultural technology and science
Decreases in fertility rates with demographic transition
Logic was sound, but prediction was a couple centuries off...
The race to feed the world
Food production currently exceeds population growth
But not everyone has enough to eat
By 2050 we will have to feed 9 billion people
Food security and undernutrition
Food security
Guarantee of an adequate, safe, nutritious, and reliable food supply
Undernutrition: inadequate calories
870 million people suffer from undernutrition
Every 5 seconds a child starves to death
Overnutrition and malnutrition
Overnutrition: too many calories each day
In the United States
1.5 billion adults are overweight
At least 500 million of those are obese
Malnutrition: inadequate nutrients
Diet lacks adequate proteins, essential lipids, vitamins, and minerals
Malnutrition can lead to diseases
Kwashiorkor
Lack of protein or essential amino acids in the diet
Children who stop breast-feeding are most at risk
Bloated stomach, mental and physical disabilities
Marasmus
Due to protein deficiency and insufficient calories
Wasting of the body
Deficiency in iodine and vitamin A are also prevalent
Going old-school
Sources of mortality in Developing Nations
Crops and Animals: Major Patterns of Food Production
Industrialized agriculture
The Green Revolution
Subsistence Agriculture
Animal husbandry
Prospects for increasing food production
Human agriculture
Relative effectiveness of Ag methods
The Green Revolution 1950s-1970s
Transfer of new agricultural technology to developing nations
Temporarily closed gap b/w production and need in some countries
Production up 4%/yr vs. population growth at 2%/yr
Heavy reliance on irrigation and fertilizers
land +33%
energy use +8000%
The green revolution
An intensification of the industrialization of agriculture in the developing world in the latter half of the 20th century that has dramatically increased crop yields produced per unit area of farmland. Practices include devoting large areas of to monocultures of crops specially bred for high yields and rapid growth; heavy use of fertilizers, pesticides, and irrigation water; and sowing and harvesting on the same piece of land more than once per year or per season.
Norman Borlaug helped launch the Green Revolution. The high-yielding, disease-resistent wheat that he bred helped boost agriculture productivity in many developing countries
Ag trends in the US
Major patterns in agriculture: Last 60 years
Resource intensive
Increasing use of fertilizers
Increasing use of chemical pesticides
Increasing use of irrigation
Energy (fossil fuel) intensive
Machinery-intensive
Refrigeration/preservation and transport
Fewer types of crops/animals
90% of food from 15 plants and 8 animal species
Industrial agriculture is a recent human invention
Traditional agriculture the work of cultivating, harvesting, storing, and distributing crops was performed by human and animal muscle power, along with hand tools and simple machines
Polycultures (many types) mixture of different crops in small plots of farmland, such as the Native American farming systems that mixed maize, beans, squash, and peppers.
Industrial agriculture a form of agriculture that uses large-scale mechanization and fossil fuel combustion, enabling farmers to replace horses and oxen with faster and more powerful means of cultivating, harvesting, transporting, and processing crops. Other aspects include irrigation, and the use of inorganic fertilizers. Use of chemical herbicides and pesticides reduces competition from weeds and herbivory by insects.
Monocultures planting vast areas with single crops in orderly, straight rows making farming more efficient, but they reduce biodiversity by eliminating habitats used by organisms in and around traditional farm fields
07_12.JPG
Pesticides can impact non-target species
Biological control pits one organism against another
Biological control (biocontrol) control of pests and weeds with organisms that prey on or parasitize them, rather than with pesticides
Integrated pest management incorporates numerous techniques, including close monitoring of pest populations, biocontrol approaches, use of synthetic chemicals when needed, habitat alternation, crop rotation, transgenic crops, alternative tillage methods, and mechanical pest removal
Pollination the process by which male sex cells of a plant (pollen) fertilize female sex cells of a plant; it's the botanical version of sexual intercourse
Unintended consequences of the Green Revolution and industrialized agriculture
National debt/interest payments in developing nations
Loss of small/family farms
Loss of traditional/alternative practices
Farm debt
Loss of culturally-specific crops
Dependence on synthetic chemical fertilizers to replenish soil fertility
Pesticide resistance in pest species (insects, weeds)
Soil erosion

Consequences
Soil loss/ degradation (nutrient lose)
Synthetic fertilizers and pesticides
Energy use transportation and storage
Irrigation (high use of water)
Loss of indigenous knowledge and crops
Animal husbandry (over population of domestic animals

Solutions
Crop rotation (soil loss, pesticides)
Shelter belts (erosions and soil loss)
Drip irrigation, contour farming (irrigation)
Conservation tillage (fertilizers and soil loss)
Irrigation boosts productivity but can damage soil
Irrigation the artificial provision of water to support agriculture
Waterlogging occurs when over-irrigation causes the water table to rise to the point that water drowns plant roots, depriving them of access to gases and essentially suffocating them
Salinization the buildup of salts in surface soil layers
Fertilizers boost crop yields but can be over applied
Fertilizer a substance that promotes plant growth by supplying essential nutrients such as nitrogen or phosphorous
Inorganic fertilizer are mined or synthetically manufactured nutrient supplements
Organic fertilizer consists of the remains or wastes of organisms and include animal manure, crop residue, fresh vegetation (green manure) and compost ( a mixture produced when decomposers break down organic matter, including food and crop waste, in a controlled environment)
The Dust Bowl United States, 1930s
In late 1800 and early 1900, farmers and ranchers removed native grasses
Dust Bowl
1930s drought, erosion = "black blizzards" of sand
1000s of farms abandoned
Displaced persons relied on governmental help to survive
The Grapes of Wrath by Steinbeck (1939)
Soil is a resource
Soil
A complex system consisting of disintegrated rock, organic matter, water, gases, nutrients, microorganisms and other detritivores
A renewable resource that can be depleted if abused
Soil influences ecosystems as much as climate, latitude, and elevation
Maintaining healthy soils
Soil degradation
Loss of soil quality and productivity
Has caused 13% loss of grain production in last 50 years
Erosion (causes soil degradation)
Removal of material from one place to another by wind or water
Deposition
Arrival of eroded material at a new place
Desertification a form of land degradation in which more than 10% of a land's productivity is lost due to erosion, soil compaction, forest removal, overgrazing, drought, salinization, climate change, water depletion, or other factors. Can result in the expansion of desert areas or creation of new ones.

Soil erosion is a global problem
Humans are the primary cause of erosion
Human activities move over 10 times more soil than all other natural process
Globally over 47 billion acres impacted by erosion/soil degradation
United States loses 5 metric tons of soil for every ton of grain harvested
Animal Husbandry
Domesticated animals as sources of protein and other nutrients

Raising animals only for food production
Leads to a lot of consequences
Global Consumption: Grain vs. Meat
Livestock need land, grain, and water
Overgrazing degrades agricultural land
Greenhouse Gasses
Animal Husbandry
Benefits
High quality protein
Cheap products

Unintended consequences
Uses of 70% of grain crops in U.S.
and therefore requires industrialized agriculture
Feedlots/CAFOs
(Mis)management of animal manure
3% of greenhouse gases
Overgrazing degrades land
Ethics?
Ethics
Do other organisms have rights to life?
Do other organisms have rights to quality of life?

Why don't we ask these same questions about plants?
QUESTION: Weighing the Issues
People in the U.S. can eat so much meat because of factory farming. However, many people are troubled by the conditions that animals are kept in. Should the quality of the animals' lives be considered when we decide how to raise food?

Yes, the quality of an animal's life is important, too.
Yes, but only if it does not interfere with access to meat.
Yes, and people should have to pay more for their meat products.
No, animals have no right to a quality of life.
I don't care. I'm not particularly fond of cows or chickens.
Overcoming Malthus
Sustainable alternatives to Industrialized Agriculture
Overcoming Malthus?
Agriculture now dependent on
soil
water
energy

Global climate change will alter the first two, and is exacerbated by third
Can we return to subsistence farming?
Cheap
Labor intensive
Low technology
Lower production per unit area
Environmental degradation
Use of marginal lands
Clearing of new lands (tropical rain forests)
Overcoming Malthus?
Eat less
Convert cash crops to food
Eat lower on the food chain
Pasture land to crop production
Alternative foods
More efficient use of captured E
Increase crop yields?
The 'new' revolution in crop yields
40% increase needed w/in 20 yrs
Sustainable
Soil, water, energy, environmental quality
More equitable?
Relies on the promise of biotechnology
Higher yields
Lower fertilizer/pesticide/water requirements
Future Ag Biomass Pyramid?
What's your global footprint?
Go to www.footprintnetwork.org
Calculate your 'global footprint' based on your lifestyle as before ...

Now recalculate assuming a strict herbivore diet.
Have we solved the problem? Yes or no, and why, by next class session...
Sustainable agriculture
Maintains the healthy soil, clean water, and genetic diversity essential to long-term crop and livestock production. It is agriculture that can be practiced in the same way far into the future while maintaining high yields
One key component of making agriculture sustainable is reducing the fossil fuel we devote to agriculture and decreasing the pollution these inputs cause
Farmer's markets
Community- supported agriculture (CSA) consumers pay farmers in advance for a share of their yield, usually a weekly delivery of produce
Soil
A complex system consisting of disintegrated rock, organic matter, water, gases, nutrients, and microorganisms
Parent material the base geologic material in a particular location (hardened lava, volcanic ash, rock or sediment deposited by glaciers, etc.)
Bedrock the continuous mass of solid rock that makes up Earth's crust.
Weathering parent material is broken down by this and it's the physical, chemical, and biological processes that converts large rock particles into smaller particles
Horizon distinct layer of soil
Soil profile the cross-section of a soil as a whole, from the surface to the bedrock
Leaching the process by which solid materials such as minerals are dissolved in a liquid (usually water) and transported to another location
Topsoil (A horizon) that portion of the soil that is most nutritive for plants and is thus of the most direct importance to ecosystems and to agriculture.

TOP Organic (litter layer), topsoil, Eluviated (leaching layer), subsoil, weathered parent material, rock (parent material) BOTTOM
Sustainable agriculture
Crop rotation
Growing different crops each year
Returns nutrients to soil
Prevents erosion, reduces pests
Wheat or corn and soybeans
Alternating the crops grown on a field from one season to the next is called
Contour farming
Plowing perpendicularly across a hill
Furrows slow runoff and capture soil
Tilling sideways across a hillside to slow water running down the slope
Sustainable agriculture
Terracing
Level platforms cut into steep hillsides
This "staircase" contains rain and irrigation water
creates level platforms for crops on steep hillsides in order to hold rainwater and reduce soil erosion.
Intercropping
Planting crops in alternating bands
Increases ground cover
Decreases pests and disease
Replenishes soil
the practice of planting different crops in strategic arrangements within the same field.

Sustainable agriculture
Shelterbelts (windbreaks)
Rows of trees along edges
Slows the wind
are rows of trees or other tall plants grown at the edges of farm fields in order to slow down winds.
Conservation tillage (no-till farming)
Residues of previous crops left in field
to prevent erosion
Soil soaks up more water
No-till farming
Farming practices that minimize disturbance to soil are
Conservation Reserve Program
Established in the 1985 farm bill
Pays farmers to stop cultivating highly erodible cropland and instead place it in conservation reserves planted with grasses and trees
Food Production: Future trends
Other sustainable trends include:
Drip irrigation directly to root zone
Breed new genetic varieties
Recycle animal wastes
Grain over animal production
Source food locally
Certified organic agriculture methods
How Productive Is Organic Farming?
Mäder's team found that soil in organic plots had
Better structure
Better supply of some nutrients
Much more microbial activity
Much more invertebrate biodiversity

See pp. 156-7
Genetically Modified Organisms
Promise
Problems
Policies
Foods can be genetically modified
Genetic engineering the process whereby scientists directly manipulate an organism's genetic material in the lab by adding, deleting, or changing segments of DNA
Able to carry genes from one species to other through bacteria
Genetically modified (GM) organisms organisms that have been genetically engineered using recombinant DNA
Recombinant DNA DNA that has been patched together from the DNA of multiple organisms. The goal is to place genes that code for certain desirable traits into organisms lacking those traits.
Transgenic an organism that contains DNA from another species
Transgenes genes that have moved between them
Biotechnology the material application of biological science to create products derived from organisms. Help develop medicines, clean up pollution, causes of cancer, etc
GM crops around the world
Transgenic Crops
Not like traditional breeding methods
Genetic engineering
Recombinant DNA technology
Incorporate desired genes into crops and animals
from viruses, insects, fungi...
Cloning of domestic animals
Genetically modified organisms
Genetic engineering: lab manipulation of DNA
Add, delete, modify
Genetically modified (GM) organisms: organisms genetically engineered using ...
Recombinant DNA: DNA created from multiple organisms
Genetically Modified Foods
Stated objectives
Disease resistance
Drought tolerance
Improved nutritional value
Incorporate human vaccines
Other unstated objectives (?)
GURT
Cross-marketing with ag chemicals

GMOs: Environmental Problems
Pest evolves resistance to genetically engineered toxin
Escape of genes to other species
"Super weeds" and/or "Super Pests"
GM Food: Other Problems
Access to new technologies
profit driven (GURT, cross marketing)
affordability in developing countries

Consumer acceptance
Labeling?
Marketing?
Food Distribution and Trade
Patterns in food trade
Food security
Famine and Hunger Hotspots
Civil Wars
Drought
Soil degradation
Government corruption/incompetence
Recent spike in hunger
Global Trade in Grain
Food Aid
Food Aid: T or F?
Alleviates chronic hunger
Helps local agriculture
Helps local economy
Contributes to local ecological deterioration
Postpones sustainable solutions
False

False
False
True

True
Lifeboat Ethics
'Lifeboat Ethics: The Case Against Helping the Poor' —Hardin (1974)
http://www.garretthardinsociety.org/articles/art_living_on_a_lifeboat.html

Too many people swamp a lifeboat...
Lifeboat Ethics
Lifeboat Ethics
homework
Causes, Consequences, and Solutions
Causes
Deforestation
Poor farming practices
Wind erosion
Consequences
Loss of topsoil
Decreased soil fertility
Lower water quality due to soil in runoff
Solutions
Planting of shelterbelts to block wind on farmland
Contour planting
No-till planting

Traditional
Relies on human and animal power
Controls pests with natural pesticides and planting of multiple crops
Many crops grown together on small plots of land
industrial
Relies on fossil fuel powered machinery
Heavy use of synthetic fertilizer
Single crops grown on large plots of land
Controls pests with synthetic pesticides
Biodiversity and conservation biology
Biodiversity encompasses multiple levels
Biodiversity (biological diversity) the variety of life across all levels of biological organization, and includes diversity in species, genes, populations, communities, and ecosystems
Species diversity the number or variety of species found in a particular region. Species richness the number of species evenness (relative abundance) the degree to which species differ in numbers of individuals (greater evenness means they differ less)
Species a distinct type of organism, a set of individuals that uniquely share certain characteristics and can breed with one another and produce fertile offspring
Genetic diversity encompasses the differences in DNA composition among individuals and this provides the raw material for adaption to local conditions
Inbreeding depression occurs when genetically similar parents mate and produce weak or defective offspring
Ecosystem diversity refers to the number and variety of ecosystems, but biologist may also refer to the diversity of communities, or habitats within some specified area

Benefits of biodiversity
Enhances food security
Organisms provide drugs and medicines
Provides ecosystem services
Helps maintain ecosystem function
Boosts economies through tourism and recreation
People value connections with nature

Biodiversity loss and extinction
Extinction occurs when the last member of a species dies and the species ceases to exist
Local extinction (extirpation) the disappearance of a population from an area, but not the entire species globally
Background extinction rate most extinctions preceding the appearance of human beings occur singularly for independent reason at a pace
Mass Extinction Events
The extinction of a large proportion of the world's species in a very short time period due to some extreme and rapid change or catastrophic event.
Earth has seen 5 mass extinction events in the past half-billion years
Ordovician, Devonian, Permo-Triassic, End-Triassic, Cretaceous-Paleogene
We are currently approaching the sixth
Archaeological evidence shows that in a case after case, a wave of extinction followed close on the heels of human arrival on islands and contients j
Species loss is accelerating as our population growth and resource consumption put increasing strain on habitats and wildlife.
Several major causes of biodiversity loss stand out
Habitat Loss
Single greatest cause of biodiversity decline
Habitat fragmentation the process by which an expanse of natural habitat becomes broken up into discontinuous fragments, often as a result of farming, logging, road building, and other types of human land use
Pollution
Air pollution degrades forest ecosystems and affects the atmosphere and climate
Water pollution impairs fish and amphibians
agricultural runoff containing fertilizers, pesticides, and sediments harms many terrestrial and aquatic species
Overharvesting
Hunting of long-lived and slow to reproduce species
Governments have passed laws to stop this
Invasive species
When non-native species are introduced to new environments, some may become invasive and push native species towards extinction
Introductions can be accidental or intentional
Climate Change
Global impacts
As we warm the atmosphere with emissions of greenhouse gases from fossil fuels combustion, we modify climate patterns and increase the frequency of extreme weather events

Conservation Biology
A scientific discipline devoted to understanding the factors, forces, and processes that influence the loss, protection, and restoration of biodiversity within and among ecosystems
Conservation geneticist a scientist who studies genetic attributes of organisms, generally to infer the status of their populations in order to help conserve them
Endangered species
Endangered Species Act the primary legislation for protecting biodiversity in the US. It offers protection to species that are endangered or threatened
Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) protects endangered species by banning international transport of their body parts
Convention on Biological Diversity aims to help nations conserve biodiversity, use it in a sustainable manner, and ensure the fair distribution of its benefits
Captive breeding individuals are bred and raised in controlled conditions with the intent of reintroducing their progeny into the wild
hotspots
Biodiversity hotspots a region that supports an especially great number of species that are endemic, found nowhere else in the world

Community based conservation is growing
When conservation biologists actively engage local people in efforts to protect land and wildlife
Water Resources
Saltwater
Freshwater
Human uses
Freshwater systems
Ocean water currents
Currents:
Driven by wind, heating/cooling, gravity, density differences, and the Coriolis effect
Oceans are complex
Oceans touch and are touched by every system
They receive all inputs, sediment, pollutants, organisms
Surface water is warmer than subsurface water
Warmed by the sun and is less dense
Deeper water is dense and sluggish
Unaffected by winds, storms, sunlight, and temperature
Ocean water also flows vertically
Upwelling: the rising of cold, deep water to the surface
Rich in nutrients
High primary productivity and lucrative fisheries
Downwelling: the sinking of warm, oxygen-rich water
Provides oxygen for deep-water life

Kelp forests
Provide shelter and food for organisms
Absorb wave energy and protect shorelines from erosion
Rocky shore intertidal
Coral reefs
Coral reef
mass of calcium carbonate mineral
skeletons of millions of tiny, invertebrate corals
Corals: Related to jellyfish w/tentacles to catch food
Derive nourishment from symbiotic algae, zooxanthallae

Mangrove forests in the tropics
Mangroves: salt-tolerant trees with unique roots
Habitat for fish, shellfish, birds
Protect coastlines from storms
Filter pollutants, stabilize soils, protect coral reefs
Produce food, medicine, tools, wood

Salt marshes
Salt marshes: along coasts at temperate latitude
Have salt-tolerant plants
Filter pollution and stabilize shorelines
Estuaries
Estuaries: water bodies where rivers flow into the ocean
Mixing fresh water with salt water
Shallow water nurtures plants that provide critical habitat for shorebirds and shellfish
Ocean fisheries
Fisheries
Modern fishing fleets deplete marine life rapidly
Overfishing is the biggest threat
We are now getting smaller fish because the tope of the food chain were the most desire and have been depleted
Techniques driftnetting, longlining and bottom-trawling
Bycatch the accidental capture of non-target animals, accounts for the deaths of millions of animals each year
Freshwater Resources
Ground water
Surface water
Lakes
Water is unequally distributed
Groundwater plays a key role
Groundwater: water beneath the surface held in pores in soil or rock
20% of the Earth's supply of fresh water
Aquifers: porous, spongelike formations of rock, sand, or gravel that hold water
Zone of aeration: pore spaces are partly filled with water
Zone of saturation: spaces are filled with water
Water table: boundary between the two zones
A typical aquifer
The Ogallala Aquifer
The world's largest known aquifer
It underlies the Great Plains of the U.S.
Unsustainable withdrawals are threatening the aquifer
Surface waters: rivers and streams
Surface water: on Earth's surface
1% of freshwater
Becomes groundwater by infiltration
Runoff: water that flows over land
Water merges in rivers and ends up in a lake or ocean
Watershed: the area of land drained by a river and its tributaries
A river may shift course over time
Floodplain: areas nearest to the river's course that are flooded periodically
Soils are fertile due to frequent deposition of silt
Good areas for agriculture
A typical lake
Ponds and lakes change over time
Oligotrophic lakes and ponds: have low-nutrient and high-oxygen conditions
They can transform into ...
Eutrophic lakes and ponds: have high-nutrient and low-oxygen conditions
Eventually, water bodies fill in completely through the process of aquatic succession
Eutrophication can also result from human-caused nutrient pollution
Human uses for water resources
Water usage
70% of our water use is for agriculture
Crop irrigation, watering of livestock
20% goes to industry, 10% for residential use
Consumptive use: water is removed from an aquifer or surface water body and is not returned (e.g., irrigation)
Nonconsumptive use: does not remove, or only temporarily removes, water
Electricity generation at hydroelectric dams
Figure 12.3 Labeled
A typical dam
The Aral Sea
Agricultural demand
"Flood and furrow" irrigation
plants use only 40% of the water applied
More efficient water use methods?
Low-pressure spray irrigation sprays water downward
Drip irrigation systems target individual plants
Match crops to land and climate
Don't grow cotton, rice, or alfalfa in arid areas
Use selective breeding and genetic modification to produce crops that require less water
Household Demand
We can reduce water use by installing low-flow faucets, showerheads, and washing machines, and toilets
High-efficiency
Xeriscaping: a type of landscaping that uses plants adapted to arid conditions


Industry and Municipalities
Manufacturers are shifting to processes that use less water = less money
Finding leaking pipes
Indicators of water quality
Chemical indicators
pH, nutrient concentrations, dissolved oxygen concentration
Physical indicators
temperature, turbidity (density of suspended particles in water)
Biological indicators
presence of harmful microorganisms, species diversity of macroinvertebrates
Pollution
The release into the environment of matter or energy that causes undesirable impacts on the health or well-being of people or other organisms
Water pollution comes in many forms and can cause diverse impacts on aquatic ecosystems and human health
Point sources discrete locations such as factories, sewer pipes, and oil tankers.
Non-point sources pollution that is cumulative, arising from multiple inputs over larger areas, such as farms, cities, and neighborhoods
Water pollution takes many forms
Toxic chemicals our waterways and coastal ecosystems have become polluted with toxic organic substances like pesticides, petroleum products, and other synthetic chemicals
Pathogens and waterborne disease disease causing organisms (pathogenic viruses, protist, and bacteria) can enter drinking water supplies that become contaminated with human waste from inadequately treated sewage or animal waste from feedlots, chicken farms, or hog farms
Nutrient pollution causes eutrophication and hypoxia (low dissolve oxygen concentrations) in surface waters
When excess nitrogen and or phosphorous enters a water body, it fertilizes algae and aquatic plants, boosting their growth. As algae dies off, bacteria in sediments consume them. Because this decomposition requires oxygen , dissolved sxygen levels decline. These levels can drop too low to support fish and shellfish, leading to dramatic changes in aquatic ecosystems
Dead zone
Harmful algal blooms excessive nutrient concentrations sometimes gives rise to population explosions among several species of marine algae that produce powerful toxins
Red tides toxic algal species that produce a red pigment that discolors the water
Water pollution takes many forms (cont.)
Biodegradable waste
Wastewater water affected by human activities and is a source of biodegradable wastes
Sediment
High sediment concentrations impair aquatic ecosystems by interfering with the respiration of fish and invertebrates and smothering benthic organisms
Oil pollution
Net and plastic debris
Thermal pollution (heating and cooling)
Freshwater pollution sources
Nutrient pollution
Nutrient pollution from fertilizers, farms, sewage, lawns, golf courses leads to eutrophication and hypoxia
Excess nitrogen and phosphorus in water boosts algal and aquatic plant growth
Spreading algae cover the surface, decreasing sunlight
Bacteria eat dead plants, reducing dissolved oxygen
Fish and shellfish die
Eutrophication is a natural process, but...
Human activities dramatically increase the rate at which it occurs
Federal legislative efforts
The Federal Water Pollution Control Act (1972)
Renamed the Clean Water Act in 1977
Made it illegal to discharge pollution without a permit
Set standards for industrial wastewater
Funded building of sewage treatment plants
Marine reserves protect ecosystems
Marine protected areas (MPAs)
Marine reserves
A typical wastewater treatment facility
HOMEWORK
Cause, Consequences, and Solutions
Causes:
Population growth
Domestic water use for homes and landscaping
Groundwater pumping for agriculture
Consequences
Water shortages
Altered plant communities
Salinization
Solutions
Improvement of wastewater treatment technology
Development of water conservation policies
Deployment of more efficient irrigation approaches
Putting it Together
Environmental systems,
Environmental issues, and
Nutrient and energy flows
Photosynthesis
Organelles called chloroplasts convert
Water (H2O) +
carbon dioxide (CO2)
to
sugars (CH2O)n + oxygen (O2).
Photosynthesis
An autotroph
Respiration and heterotrophs
Organisms release stored energy via respiration
Burns sugar molecules with oxygen, releasing CO2, H2O and stored chemical energy
Respiration occurs in both autotrophs and in the heterotrophs (animals, fungi, most microbes) that eat them
Cellular respiration
The opposite of the equation for photosynthesis.
Energy flows, nutrients cycle

Organic compounds
Compounds based on carbon atoms
Very diverse set of compounds
Vitally important to life
sugars,
oils,
proteins
Macromolecules
Major classes:
Proteins
Nucleic acids
Carbohydrates
Lipids
(The first three are polymers)
Proteins
Consist of chains of amino acids folded into complex shapes



For structure, energy, immune system, hormones, enzymes
Nucleic acids
Paired strands of nucleotides make up the DNA double helix.
Carbohydrates
Carbohydrates consist of chains of sugars.

For energy, and structure (cellulose, chitin)
Lipids
Hydrophobic-do not dissolve in water











Include fats and oils; phospholipids; waxes; steroids
Chemical structure of DDT
Bioaccumulation and Biomagnification
A typical polychlorinated biphenyl (PCB)





What will happen to this molecule?
Building Blocks of Life
Organic Matter
Carbohydrates
Fats and Oils
Proteins
Nucleic acids
Inorganic Matter
Macronutrients
Nitrogen (N)
Phosphorus (P)
Sulfur (S)
Potassium (K)
Micronutrients
Calcium (Ca)
Iron (Fe)
Cobalt (Co)
Selenium (Se)
...and several others
Liebig's Law of the Minimum
Growth of autotrophs limited by nutrient (macro or micro) that's least available
Limiting Nutrients
Limiting Nutrients
Honeydew, baby!
Generalized biogeochemical cycle
Spontanous flow
Non-spontaneous flow
Bioavailability
Organisms require chemical elements in a specific form to be usable
ex: C unavailable to mammals in form of CO2, available in form of C6H12O6

Therefore, conversion of element from one form to another is another important non-spontaneous flow
Nitrogen Cycle
Phosphorus Cycle
Case study: The Gulf Dead Zone
Zone of hypoxic water at mouth of the Mississippi River
Annual change
1000 to >22,000 km2

A paradox of enrichment...
The Mississippi Watershed
Satellite photo of nutrient input
Nutrient inputs over time
How the dead zone forms
DO Monitoring
Change in area over time
Test your understanding
What would a major hurricane do? What about a series of moderate hurricanes?
What effect will the Deepwater Horizon spill have?
Can phenomena flow upriver?
How the dead zone forms
Gulf oil spill microbiology
Salmon as biological pumps
Chapter 13: Air Pollution
Outdoors: Criteria pollutants and the Clean Air Act
Indoors: Smoke, Radon, VOCs,...
Textbook
The Atmosphere the layer of gases that envelops our planet. It moderates our climate, provides oxygen, shields us from meteors and from hazardous solar radiation, and transports and recycles water and nutrients.
The atmosphere is layered
Troposphere: the bottommost layer. Air movement drives the planet's weather. Is thin compared to the other layers, but it contains three-quarters of the atmosphere's mass. Tropopause limits mixing between the troposphere and the stratosphere.
Stratosphere: middle. Drier and less dense than the troposphere. Its gases experience little vertical mixing so once substances (including pollutants) enter it, they tend to remain for a long time. Warms the altitude (it's ozone and oxygen absorbs the sun's ultraviolet radiation) by absorbing and scattering UV radiation, it reduces the amount that reaches the Earth's surface. Ozone layer above sea level, that contains most of the ozone in the atmosphere
Mesosphere: above the stratosphere. Temperature decreases with altitude and where incoming meteors burn up
Thermosphere: above the mesosphere
Exosphere: merges into space
The sun influences weather and climate
A large amount of energy from the sun constantly bombards the upper atmosphere. 70% of the solar energy is absorbed by the atmosphere and planetary surface (the rest is reflected back into space)
Land and surface water absorb solar energy and the emit thermal infrared radiation, which warms the air and causes some water to evaporate. As a result, air near Earth's surface tends to be warmer and moister than air at higher altitudes
This causes convective circulation a circular current of air, water, magma ,etc) driven by temperature differences. In the atmosphere, warm air rises into regions of lower atmospheric pressure, where it expands and cools and then
Inversions affect air quality
Large-scale circulation systems produce global climate patterns
Stratospheric ozone depletion: a global scale problem
What is stratospheric ozone?
What are ozone depleting substances?
What solutions have we developed?
The atmosphere is layered
Earth's four atmospheric layers have different temperatures, densities, and chemical composition
Troposphere
Bottommost layer (11 km [7 miles])
Responsible for Earth's weather
The air gets colder with altitude
Tropopause
The boundary that limits mixing between the troposphere and stratosphere
The atmosphere is layered
Stratosphere
11-50 km (7-31 mi) above sea level
Drier and less dense, with little vertical mixing
Gets warmer with altitude
Ozone layer
Blocks UV radiation
Mesosphere
Low air pressure
Gets colder with altitude
Thermosphere
Top layer

Ozone depletion
Ozone in the lower stratosphere absorbs the sun's ultraviolet (UV) radiation
UV radiation can damage tissues and DNA
Ozone-depleting substances
Human-made chemicals that destroy ozone
The major ODS chemicals: Halocarbons
Human-made compounds made from hydrocarbons with added chlorine, bromine, or fluorine

Synthetic chemicals deplete stratospheric ozone
Chlorofluorocarbons (CFCs)
Halocarbons used as refrigerants, in fire extinguishers, in aerosol cans, etc.
They stay in the stratosphere for a century
Sunlight releases chlorine atoms that split ozone
Ozone hole
Decreased ozone levels over Antarctica
We are solving ozone depletion with the Montreal Protocol
Montreal Protocol (1987)
196 nations agreed to cut CFC production in half by 1998
Later agreements deepened cuts, advanced timetables, and addressed other ozone-depleting chemicals
Industry shifted to safer alternative chemicals
We stopped the Antarctic ozone hole from getting worse
Challenges still face us
CFCs will remain in the stratosphere for decades
It can serve as a model for international environmental cooperation
The ozone layer has stopped growing
Outdoor (ambient) air pollution
Air pollutants: gases and particulate material added to the atmosphere
Can affect climate
Can harm people or other organisms
Natural sources
Winds blowing over arid terrain
huge amounts of dust
Volcanoes
particulate matter, sulfur dioxide, and other gases.
Fires
soot and gases.

Exacerbated by farming, grazing, erosion, desertification, clearing forests
Anthropogenic air pollution
Sources
Point sources: specific spots where large quantities of pollutants are discharged (power plants and factories)
Non-point sources: more diffuse, consisting of many small sources (automobiles)

Types of pollutants
Primary pollutants: directly harmful and can react to form harmful substances (soot and carbon dioxide)
Secondary pollutants: form when primary pollutants interact or react with constituents of the atmosphere
Air pollution operates at many scales (duration and area)
Clean Air Act (CAA)
Passed in 1970 (amended 1990)
Provides:
NAAQS for criteria air pollutants
Reduction from mobile sources
New stationary source performance standards
Limits on emissions
Funds for pollution-control research
Right to sue polluters
The EPA sets standards
Environmental Protection Agency (EPA) sets nationwide standards
State Implementation Plans (SIPs)
States monitor air quality and develop, implement, and enforce regulations.
If a state's plans are not adequate, the EPA can take over enforcement.
Six EPA criteria pollutants
Carbon monoxide (CO)
Sulfur dioxide (SO2)
Particulate matter
Nitrogen oxides (NOx)
Volatile organic compounds (VOCs)
Lead
Carbon Monoxide-CO
Colorless, odorless

Binds strongly with hemoglobin
Blocks transport of oxygen by the blood
Headaches, dizziness, and death

Produced by incomplete combustion
Mobile & stationary sources
Industrial Smog
Sulfur Dioxide-SO2
Constricts airways, changes respiratory and pulse rates
50,000 deaths/year U.S.
Sources vary
Volcanic eruptions and sea spray
Fossil Fuel Combustion
Smelting Ores
Mixes with water to make sulfuric acid
Particulate Matter
Mixture of solid particles and liquid droplets
Aerosol
Dust
Fumes
Mist
Smoke or soot
Categorized by size
PM10
PM2.5
Size of Particulates
Effects of Particulates
Respiratory ailments
Bronchitis, pneumonia, emphysema, asthma
Genetic mutations
"Weekend Effect"
Nitrogen Oxides-NOx
NO, NO2, NO3, N2O, N2O3, N2O4, and N2O5
Effects
Some can form nitric acid
Precursor to many other pollutants
Sources
Thermal NOx when fuel is burned with air at high temperatures
This leads to burning nitrogen gas also...
Volatile Organic Compounds (VOCs)
Carbon-based chemicals from a variety of sources
Solvents, auto exhaust, paints, industrial activity, consumer products
Some are directly toxic
Benzene, formaldehyde, many others
Can also react to produce secondary pollutants, such as tropospheric ozone (O3)
Photochemical Smog
Ozone as a pollutant
Tropospheric ozone (O3): a colorless gas with a strong odor
Secondary pollutant created from interactions of sunlight, heat, nitrogen oxides, volatile carbons
A major component of smog
Poses a health risk as a result of its instability
Most frequently exceeds the EPA standard

Stratospheric ozone is a different story—more later
Lead
Elemental lead added to gas and used in industrial metal smelting
Bioaccumulates and causes nervous system malfunction
Banned in gasoline in developed, but not in developing, countries
The CAA is successful
Innovations driven by CAA
Cleaner-burning vehicles and catalytic converters decrease carbon monoxide.
Permit-trading programs and clean coal technologies reduce SO2 emissions.
Phaseout of leaded gasoline
Improved technologies and federal policies
Scrubbers: technologies that chemically convert or physically remove pollutants before they leave the smokestacks
Scrubber technology
Toxic substances also pollute
Toxic air pollutants: substances known to cause cancer, reproductive defects, and/or neurological, development, immune system, or respiratory problems

The Clean Air Act identifies 188 toxic pollutants.
Emissions decreased 35% between 1990 and 2002.
CAA is controversial
President G.W. Bush proposed modifications
Abolish 'New source reviews': during which old utility plants have to install the best available technology when upgrading
Clear Skies Initiative (2003) would have:
Allowed 42 million more tons of pollution per yr
raised current cap on nitrogen oxide pollution, allowing 68% more NOx pollution
delayed improvement of sulfur dioxide (SO2) pollution levels required by CAA
delayed enforcement of smog-and-soot pollution standards until 2015
Transboundary issues
Acidic deposition: the deposition of acid, or acid-forming pollutants, from the atmosphere onto Earth's surface
Acid rain: precipitation of acid
Atmospheric deposition: the wet or dry deposition on land of pollutants
Acid rain from NOx and SO2: Distance effects
Acid rain in the US
Acid Deposition and Buffering
Buffering of acid rain takes place when limestone (CaCO3) supplies bicarbonate ions (HCO3-)
The bicarbonate ion (HCO3-) combines with hydrogen ions to neutralize acid rain




Geographic differences
In areas that have large amounts of calcium carbonate (western U.S.) acidity is buffered
In other areas, such as New England or upstate NY, acid precipitation quickly lowers pH
Effects
Nutrients are leached from topsoil.
Metal ions (aluminum, zinc, etc.) converted into soluble forms that pollute water.
Damages agricultural crops
Affects surface water and kills fish
Widespread tree mortality
Erodes stone buildings, corrodes cars, erases writing on tombstones and other monuments
Developing nations
Factories and power plants have little or no pollution control.
Wood and charcoal are used to cook and heat homes.
Global patterns in air pollution
Indoor air pollution
Indoor air contains higher concentrations of pollutants than outdoor air.

The average U.S. citizen spends 90% of the time indoors.
6,000 people die per day from indoor air pollution
Indoor air pollution
Secondhand smoke
Eye, nose, and throat irritation, asthma, cancer
Radon
radioactive gas resulting from natural decay of rock, soil, or water
20,000 deaths a year in the U.S.
Volatile organic compounds (VOCs)
Released by everything from plastics and oils to perfumes and paints
some are carcinogenic, some are toxic through other pathways
Organisms
pathogenic bacteria, mold, fungi
Sources of indoor air pollution
Indoor air pollution in the developing world
Homes have little to no ventilation...
...wood, charcoal, dung for fuel...
...PM and carbon monoxide
estimated 4.3 million deaths per year
(more than HIV, malaria, tuberculosis)

Multiple Choice HW
Lead: Before the 1980s, gasoline combustion was a major source of this pollutant
Tropospheric ozone: This pollutant's chemical structure is three bonded oxygen atoms. Its concentration is strongly influenced by sunlight levels and air temperature.
Particulate Matter: Pollutants in this category are classified according to diameter.
Carbon Monoxide: This pollutant deprives organisms of oxygen by binding to the hemoglobin in red blood cells.
Nitrogen dioxide: This pollutant contributes to the formation of photochemical smog and acid deposition.
Sulfur dioxide: A very high percentage of the emissions of this pollutant comes from coal combustion.


Which of the following layers of the atmosphere is responsible for the weather that we experience on the surface of Earth? Troposphere
Which gas makes up 78% of the molecules in the atmosphere? N2—nitrogen
What process depends upon the cyclical, vertical movement of air currents: sinking cold, dense; and rising warm, less dense air masses? Convective circulation
Which of the following can trap pollutants at ground level and cause dangerous smog? Thermal inversions
Point sources of air pollution are __________. specific spots--such as a factory's smokestacks--where large quantities of pollution are discharged
A __________ pollutant interacts with a part of the atmosphere and becomes a __________ pollutant. Primary; secondary
The EPA tracks six "criteria" air pollutants. Which of these is true of the criteria air pollutants? Total emissions of the six have declined by over 50% since 1970
What releases NO and VOC into the atmosphere, initiating the formation of photochemical smog in cities like Los Angeles and Tehran? Vehicle exhaust



Photochemical smog
Concentrations are elevated by hot, sunny days
A reaction between pollutants and atmospheric compounds that creates over 100 different chemicals:
Most pronounced in cities prone to inversion events:
Acid disposition
Forms from emissions of sulfur dioxide:
Leaches plant nutrients from soils:

What is largely responsible for the ozone hole? chlorofluorocarbon refrigerants (CFCs)
ozone is made of __________ and is broken down by __________. Oxygen; chlorine
In which way does acid deposition originate? Through fossil fuel combustion by cars, electric utilities, and industrial facilities
What happens when acids from acid deposition hit topsoil? Plants and soil organisms are harmed
Most of the indoor air pollution in developing countries comes from burning fuelwood
Which two pollutants are the top two responsible for lung pollution in the United States? Cigarette smoke and radon gas
Ch. 14 Consequences of Global Climate Change
Climate Models
Impact Predictions
IPCC AR4 WG II (say what?)
Radiative Forcing (W per m2)
14_10b.jpg
14_10a.jpg
Trends in Greenhouse Gases
SE 14-16 Anthropogenic climate change
What about the future?
Prediction depends on:
Understanding climate system
Projecting human activity

Coupled general circulation models (climate models)
Computer simulations of climate trends
Becoming more reliable in predicting climate change
SE 14-16 Anthropogenic climate change
SE 14-16 Anthropogenic climate change
SE 14-16 Anthropogenic climate change
SE 14-16 Anthropogenic climate change
Current and future impacts
Intergovernmental Panel on Climate Change (IPCC)
An international panel of scientists and government officials established in 1988
Has presented a series of reports on the synthesis of scientific information concerning climate change
Our dynamic climate
Intergovernmental Panel on Climate Change (IPCC) provides evidence that:
Climate is changing, we are the cause, and this change is already exerting impacts that will become increasingly severe
Issues surrounding extent and consequences of global climate change are fastest-moving area of research
Simplified Climate System
Are humans responsible?
Yes
IPCC: >90% likely that most global warming due to humans
Direct evidence from: direct measures of anthropogenic greenhouse gasses, isotope ratios of CO2, recent historical data, etc...
Models that best fit data include human impacts
Despite broad scientific consensus, outdated debate lingered into mid-2000s
Skeptics funded by energy industry
Use subsets of all data; present interpretations not common in scientific community
Aimed to cast doubt on the scientific consensus
Today, research focuses on extent of change
Emissions Scenarios
Predicted future patterns
Effects on climate forcings
Climate Models: Components
Radiative forcing
SRES Climate Scenarios
IPCC Projections
Impacts of Climate Change
Facing uncertainty
Predicting complexity
Informing policy
U.S. Global Change Research Program
IPCC AR4 WG II
Intergovernmental Panel on Climate Change
Assessment Report 4 (2007)
Working Group II
Assess vulnerability of socio-economic and natural systems
Predict negative, positive consequences
Present options for adapting to it
Changes in precipitation
Precipitation change will vary by region
Temperatures rise 0.2°C/10 yr
Temperature change will vary by region
Temperature changes are greatest in the Arctic


Ice caps shrinking

Storms are increasing

Sea ice is thinning
Worldwide, glaciers are melting rapidly
Melting snow and ice
Mountaintop glaciers are disappearing
In Glacier National Park, only 27 of 150 glaciers remain
Risks of sudden floods as ice dams burst
Reducing summertime water supplies

Melting of the Greenland ice sheet is accelerating

As ice melts, darker, less-reflective surfaces are exposed and absorb more sunlight, causing more melting
Rising sea levels
Rising sea levels
As glaciers and ice melt, increased water will flow into the oceans
As oceans warm, they expand

Outcome:
IPCC predicts mean sea level to be 18-59 cm (7-23 in) higher than today's at the end of the 21st century
Leads to beach erosion, coastal floods, and intrusion of salt water into aquifers
Effects on organisms/ecosystems
Global warming modifies temperature-dependent phenomena
Timing of migration, breeding

Shifts in geographic range of organisms
Animals and plants will move towards the poles or upward in elevation
20-30% of all species will be threatened with extinction

Plants act as carbon sinks; fewer plants means more CO2 in the atmosphere
Climate changes cause extinction
Societal impacts
Agriculture:
growing seasons shortened, crops more susceptible to droughts and failure;
crop production will decrease, worsening hunger
Forestry:
increased insect and disease outbreaks,
increased chance of forest fires (especially in rainforests)
Health:
heat waves and stress can cause death, respiratory ailments,
expansion of tropical diseases,
increased mortaliaty from storms
hunger-related ailments
Economic Impacts
Costs will outweigh benefits

Will cost 1-5% GDP on average globally
Inequality in costs among developed, developing nations

Climate change could cost 5-20% of GDP by 2200
Effects on Ecosystems, Human Health
Regional Impacts
Adaptation vs. Mitigation
Adaptation, Mitigation
Adaptation is essential to cope with the unavoidable
Mitigation is essential to prevent the avoidable
John Holdren's view
"We basically have three choices - mitigation, adaptation, and suffering.
We're going to do some of each. The question is what the mix is going to be.
The more mitigation we do, the less adaptation will be required, and the less suffering there will be."
IPCC Call to Immediate Action
"Due to the inertia of both climate and socio-economic systems, the benefits of mitigation actions initiated now may result in significant avoided climate change only after several decades. This means that mitigation actions need to start in the short-term in order to have a medium-and longer-term benefits and to avoid lock-in of carbon-intensive technologies."
Chapter 14: Global Climate Change
Causes
Consequences
Solutions
Rising seas flood the Maldives
Independent nation of islands in the Indian Ocean
The islands will be submerged by rising seas accompanying global climate change
The government has already evacuated residents from of the lowest-lying islands

Next week: What can or should be done to address this?
What is climate change?
Climate
an area's long-term atmospheric conditions
includes temperature, precipitation, & storm frequency
Global climate change
Describes an array of changes in aspect of Earth's climate, such as temperature, precipitation, and the frequency and intensity of storms
Change in Earth's climate over time
via natural processes throughout the history of earth
Increasingly affected by human activity
Global warming
an increase in Earth's average temperature
Primary determinants of climate
sun
supplies most of our planet's energy
without it, the Earth would be dark and frozen
atmosphere
Earth's atmosphere (and clouds) can both absorb and reflect solar radiation
without it, the Earth's temperature would be much colder
oceans
shape climate by storing and transporting heat and moisture
Solar output influences climate


The Sun varies in the radiation it emits
Variation in solar energy (i.e., solar flares) has not been great enough to change Earth's temperature
Milankovitch cycles
Periodic changes in Earth's rotation and orbit around the Sun
Alter the way solar radiation is distributed over Earth's surface
Trigger long-term climate variation such as periodic glaciation
Fate of Incoming Solar Energy
Heat Balance of Earth
Work Done by Incoming Energy
Heat Drives Convection Cells
Convection Cells Drive Rainfall
Convection Cells Drive Winds
Winds Drive Ocean Currents
Ocean absorption buffers climate
Ocean water exchanges tremendous amounts of heat with the atmosphere, and ocean currents move energy from place to place
Ocean holds 50 times more carbon than the atmosphere and absorbs it from the atmosphere
Buffering against rapid global warming
But warmer oceans absorb less CO2
gases are less soluble in warmer water

Positive feedback effect
Ocean Currents Drive Thermohaline Circulation
Thermohaline circulation
Global current system in which warmer, fresher water moves along the surface; and colder, saltier water moves deep beneath the surface
Warm surface water carries heat to Europe
North American Deep Water (NADW) = the deep portion of the thermohaline circulation, consisting of dense, cool water that sinks
Thermohaline circulation
Some data suggest thermohaline circulation is slowing
Why?
If Greenland's ice melts, freshwater runoff would dilute ocean waters, making them less dense
This would disrupt NADW
Greenhouse gases
Greenhouse gases: a gas that absorbs infrared radiation released by Earth's surface and then warms the surface and troposphere by emitting energy, thus giving rise to the greenhouse effect
Atmospheric gases that absorb infrared radiation
Include water vapor(H2O), ozone (O3), carbon dioxide(CO2), nitrous oxide (N2O), methane (CH4), and chlorofluorocarbons (molecules of C + Cl and/or F attached)

Bonds between atoms in a molecule absorbe radiation
greenhouse gases re-emit some of this energy as infrared (heat) energy
Heat Balance of Earth
The Greenhouse Effect
After absorbing radiation, greenhouse gases re-emit infrared energy
Some energy is lost to space...
...But some energy travels back downward, warming the atmosphere and planet's surface

Key factor is the amount of heat re-emitted by atmosphere
Too little? = Ice Ages
Just right? = Historic climate
Too much? = current (and past) warming trends
Are all molecules the same?
U.S. emissions of major greenhouse gases
CO2 is primary concern
Extremely abundant
The major contributor to global warming

Long residence time in atmosphere

Human activities have boosted atmospheric concentrations from 280 parts per million (ppm) to 400 ppm
Highest levels in more than 650,000 years

What causes elevated CO2?
Burned fossil fuels
Transferred large amounts of carbon dioxide from lithospheric reservoirs into the atmosphere
Deforestation
Forests serve as sinks for recently active carbon
Their removal reduces the biosphere's ability to absorb carbon dioxide from the atmosphere
Other greenhouse gases
Methane
fossil fuel deposits, livestock, landfills, and crops such as rice
Nitrous oxide
feedlots, chemical manufacturing plants, auto emissions, and synthetic nitrogen fertilizers
Ozone
risen due to photochemical smog
Halocarbon gases (CFCs)
are declining due to the Montreal Protocol
Water vapor
Can re-emit infrared, and hold heat energy...
...and could increase cloudiness, which might slow global warming by reflecting more solar radiation back into space
Aerosols may cool atmosphere
Microscopic droplets and particles that have either a warming or cooling effect
Soot, or black carbon aerosols, cause warming by absorbing solar energy
But, most tropospheric aerosols cool the atmosphere by reflecting the Sun's rays
Sulfate aerosols produced by fossil fuel combustion may slow global warming, at least in the short term
Volcanic eruptions reduce sunlight reaching the earth and cool the Earth
Radiative Forcing (watts per m2)
Radiative forcing
The change in energy content caused by a given factor
Positive forcing warms the surface
Negative forcing cools the surface

Compared with the pre-industrial Earth, Earth is experiencing radiative forcing of +1.6 watts/m2

This is sufficient to alter the global climate
What about the past?
Proxy indicators
Ice caps, ice sheets, and glaciers hold clues to Earth's climate
Trapped bubbles in ice cores show atmospheric composition, greenhouse gas concentration, temperature trends, snowfall, solar activity, and frequency of fires
Other proxy indicators
Scientists need to combine multiple records to get a global perspective
Cores in sediment beds preserve pollen grains and other plant remnants
Tree rings indicate age, wetness of the season, droughts, and seasonal growth
Researchers also gather data on past ocean conditions from coral reefs
What about the present?
Concentrations of CO2 have increased over 21% just since the mid-1950s
Other greenhouse gasses also show rapid increases
Methane
Nitrous oxide
Sulfur compounds

Climate Models
Components
Feedbacks
Thresholds
What about the future?


Coupled general circulation models (climate models)
Computer simulations of climate trends
Becoming more reliable in predicting climate change
How do we make predictions?
Climate models!
What do we need?
Initial conditions
Complex climate system
Feedbacks
Threshold effects
Emissions scenarios
Radiative forcing
Climate models: Feedback (+)
Melting of glaciers and ice caps
Water vapor
Decay of biomass
Forest growth replacing tundra
Release of methane
CO2 dissolved in oceans
Glacial descent or destabilization
Climate models: Feedback (-)
Cloud formation
Photosynthesis
Infrared radiation to space
Increased snowfall
Disrupted thermohaline circulation
Threshold Effects?
How far can the climate system change before it 'breaks' in some way?
Ex: Interrupting thermohaline current in global ocean system that eliminates NADW—cooling Europe to a subarctic tundra biome
Thermohaline Circulation
Net primary productivity
Results from three simulations
Figure (a) shows natural climate factors only

Figure (b) shows only human factors
Emissions of greenhouse gases

Figure (c) shows both factors




Which of these would NOT contribute to a global increase in temperature? Planting trees
Switching from fossil fuels to _____ energy would significantly decrease the release of carbon dioxide into the atmosphere. Solar, nuclear, and geothermal
Which three factors have the greatest effect on Earth's climate? The sun, the atmosphere, and the ocean
What is the greenhouse effect? A warming of Earth's atmosphere by greenhouse gases that trap reflected heat rather than allow it to escape into space
Which of the following contributes to atmospheric cooling? aerosols (particularly sulfur compounds) and dusts


Scientists evaluate concentrations of gases and other atmospheric constituents from the distant past by examining which of the following? Gas bubbles trapped in ice
What initiative or group is responsible for the most reviewed and widely accepted reports that we have on climate change? Intergovernmental Panel on Climate Change (IPCC)
Why are over one-sixth of the world's people at risk for running out of drinking water? Glaciers in many areas are melting
How are warming temperatures causing a vicious cycle (positive feedback) that is leading to enhanced warming? Ice and snow reflect light, and as they melt, Earth absorbs more of the sun's rays
How is global warming most significantly affecting coral reefs and sea life? Increase concentrations of carbon dioxide are being absorbed by the oceans.

Factors that contribute to warming
Tropospheric ozone (O3)
Carbon dioxide (CO2) from fossil fuel combustion
Methane (CH4) from decomposition and feedlots
Nitrogen oxides (N2O) from denitrification and fossil fuel combustion
Parts of Earth's surface with low reflectivity (low albedo)
Black carbon aerosols and soot particles

Factors that contribute to cooling
Parts of Earth's surface with high reflectivity (high albedo)
Condensed water vapor (cloud albedo)


Decrease plant growth
decrease CO2
decrease H2O
decrease sunlight

Increase plant growth
increase CO2
increase H2O
increase sunlight


What two processes emit the most carbon in the United States? Electricity generation and transportation
Which greenhouse gas is produced by the raising of cattle? Methane
Which of the following is an example of mitigation rather than adaptation for global climate change? building more solar panels to generate electricity instead of more coal-fired power plants
Nonrenewable Energy Sources, Their Impacts, and Energy Conservation
Chapter 15
Sources of Energy
We rely mostly on fossil fuels
Fossil fuels: highly combustible substances formed underground over millions of years from the buried remains of ancient organisms
we use three main fossil fuels: coal, oil, and natural gas.
Fossil fuels provide most of the energy that we buy, sell, and consume because their high energy content makes them efficient to ship, store, and burn.
We use fossil fuels for transportation, heating, and cooking, and also to generate electricity: a secondary form of energy that we can transfer over long distances and apply to many uses
Given our accelerating consumption, we risk using up these nonrenewable fuel resources
Energy is unevenly distributed
Some regions of the globe have substantial reserves of oil, coal, or natural gas, whereas other have very few
Consumption rates across the world are also unequal
Societies differ in how they use energy
It takes energy to make energy
Net energy: expresses the difference between energy returned and energy invested
Net energy= energy returned-energy invested
EROI - energy returned on investment:
EROI= energy returned/energy invested
Higher EROI ratios mean that we receive more energy from each unit of energy that we invest
Fossil fuels are widely used because their EROI ratios have been high
Ratios can change
Ratios rise as technologies to extract and process fuels become more efficient
Ratios fall when resources are depleted and becomes harder to extract
Where will we turn for energy?
Fossil fuels advanced the standard of living
New Ideas
Using potent extraction methods such as hydraulic fracturing to free gas and oil tightly bound in rock layers
Using powerful new machinery and techniques to squeeze more fuels from sites that were already extracted
Drilling deeper underground, further offshore, and into Arctic seabed
Pursuing new fossil fuels
Better ideas
Hasten the development of renewable energy sources
Fossil Fuels: Their formation, Extraction, and Use
Fossil Fuels are formed from ancient organic matter
Fossil fuels form only after organic material is broken down over millions of years in an anaerobic environment: one with little to no oxygen (like the bottoms of lakes, swamps, and shallow seas)
The fossil fuels we burn today were formed from the tissues of organisms that lived 100-500 million years ago.
Fossil fuels form only under certain conditions, they occur in isolated deposits
Geologist searching for fossil fuels drill cores and conduct ground, air, and seismic surveys to map underground rock formations and predict where fossil fuel deposits might occur
Fossil Fuels are formed from ancient organic matter (cont.)
Coal
The most abundant fossil fuel
A hard blackish substance formed from organic matter compressed under high pressure, creating dense, solid carbon structures
Coal typically results when water is squeezed out of such material as pressure and heat increase over time and when little decomposition takes place
strip mining: To extract coal from deposits near the surface, in which heavy machinery scrapes away huge amounts of Earth
Subsurface mining: for deposits deep underground. Digging vertical shafts and blasting out networks of horizontal tunnels to follow seams, or layers of coal
Mountaintop removal mining: mining coal on immense scales in the Appalachian Mountains, blasting away entire mountaintops
Fossil Fuels are formed from ancient organic matter (cont.)
Oil and Natural Gas
Oil/Crude Oil: The sludge like liquid that contains a mix of various hydrocarbon molecules
Natural Gas: a gas consisting of methane (CH4) and lesser, variable, amounts of other volatile hydrocarbons.
Petroleum: oil is known by this term
Formed from organic materials that drifted down through coastal marine waters millions of years ago and was buried in sediments on the ocean floor.
This organic material was transformed by time, heat, and pressure into today's natural gas and crude oil.
Two processes give rise to natural gas
Biogenic gas: created at shallow depths by the anaerobic decomposition of organic matter by bacteria
One source of biogenic natural gas is the decay process in landfills and landfill operators are now capturing this gas to sell as fuel
Thermogenic gas: results from compression and heat deep underground.
It may form directly or from coal or oil altered by heating
Most gas extracted commercially is thermogenic and is found above deposits of oil or seams of coal, so it is often extracted along with those fuels
Fossil Fuels are formed from ancient organic matter (cont.)
Oil and Natural Gas (cont.)
Underground pressure tends to drive oil and natural gas upward through cracks and fissures in porous rock until they become trapped under a dense, impermeable rock layer
Oil and gas companies employ geologist to study rock formations to identify promising locations
Once such a location is identified, a company conducts exploratory drilling: drilling small holes to great depths. If enough oil or gas is encountered, extraction may begin.
Because oil and gas are under pressure while in the ground, they rise to the surface when a deposit is tapped. Once pressure is relieved and some portion has risen to the surface, the remainder will need to be pumped out
Fossil Fuels are formed from ancient organic matter (cont.)
Unconventional fossil fuels
Oil sands
Also known as tar sand consist of moist sand and clay containing 1-20% bitumen, a thick and heavy form of petroleum
Represent crude oil deposits degraded and chemically altered by water erosion and bacterial decomposition
Extracted two ways:
For deposits near the surface, a process akin to strip mining for coal or open-pit mining for minerals is used.
Fossil Fuels are formed from ancient organic matter (cont.)
Unconventional fossil fuels
Oil shale
Sedimentary rock filled with kerogen (organic matter) that can be processed to produce a liquid form of petroleum
Oil shale is formed by the same processes that form crude oil but occurs when kerogen was not buried deeply enough or subjected to enough heat and pressure to form oil
Shale Oil: a liquid form of petroleum extracted from deposits of oil shale
Methane hydrate/ methane clathrate/methane ice
An ice like solid consisting of molecules of methane embedded in a crystal lattice of water molecules

Economies determines how much will be extracted
Proven recoverable reserve: the amount of a given fossil fuel in a deposit that is technologically and economically feasible to remove under current conditions
Refining produces a diversity of fuels
Once we extract oil or gas, it must be processed and refined
At a refinery, hydrocarbon molecules are separated by size and are chemically transformed to create specialized fuels for heating, cooking, and transportation and to create lubricating oils, asphalts, and the precursors of plastics and other petrochemical products
Fossil fuels have many uses
Coal
Cook, heat, and fire pottery, coal-fired steam engines, generate electricity
Natural gas
Generate electricity in power plants, to heat and cook
Oil
Fuel for cars, diesel for trucks, and jet fuel


We are depleting fossil fuels reserves
reserves-to-production ration (R/P ratio): to estimate how long remaining oil will last
Dividing the amount of remaining reserves by the annual rate of production (extraction and processing)

Peak oil will pose challenges
Hubbert's Peak: The peak in production of crude oil in the US, which occurred in 1970 just as Shell Oil geologist M. King Hubbert has predicted in 1956
Hubbert analyzed data on technology, economics, and geology, and predicated that worldwide oil production would peak in 1995
A divergence of supply and demand could have momentous consequences that profoundly affect our lives
Lacking cheap oil with which to transport goods long distances, today's globalized economy would collapse into isolated local economies
More optimistic observers argue that as oil supplies dwindle, rising prices will create powerful incentives for businesses, governments, and individuals to conserve energy and to develop alternative energy sources
Reaching further for fossil fuels... and coping with the impacts
Mountaintop mining extends our reach for coal
Mountaintop removal mining has brought coal extraction and its impacts to a whole new level
The massive scale of mountaintop removal mining makes it economically efficient
The technique can cause staggering volumes of rock and soil to slide downslope, degrading or destroying entire hillsides, polluting or burying streams and disputing life for people nearby
Magnifies many of the impacts of traditional strip mining for coal, which unleashes soil erosion and destroys large areas of habitat
These mining methods send chemical runoff into waterways in the form of acid drainage, whereby sulfide minerals in newly exposed rock surfaces react with oxygen and rainwater to produce sulfuric acid
Secondary extraction produces more fuel
Primary extraction: the initial drilling and pumping of oil or gas
At a typical oil or gas well, as much as 2/3 of a deposit may remain in the ground
Secondary extraction: the extraction of crude oil remaining after primary extraction by using solvents or by flushing underground rocks with water or steam
Solvents are injected, underground rocks are flushed with water or steam, or hydraulic fracturing may be used
More expensive
Directional drilling reaches more fuel with less impact
Directional drilling: a drilling technique in which a drill bores down vertically and then bends horizontally in order to follow layered deposits for long distances from the drilling site. This enables us to extract more fossil fuels with less environmental impact at the surface
Hydraulic fracturing expands our access to oil and gas
For oil and natural gas trapped tightly in shale or other rock, oil and gas companies now use hydraulic fracturing
Chemically treated water under high pressure is pumped into layers of rock to crack them and sand or small glass beads holds the cracks open as the water is withdrawn
Gas or oil then travels upward through the system of fractures
By unlocking formerly inaccessible deposits of shale gas and tight oil, hydrpfracking has ignited a boom in extraction in the US
We are drilling farther offshore
Geologist estimate that most of the US gas and oil remaining occurs offshore and that deep water sites in the Gulf may hold 59 billion barrels of oil
As oil and gas are depleted at shallow-water sites and as drilling technology improves, the industry is moving into deeper and deeper water
Deep offshore drilling is boosting oil and gas production, but it poses risks
Melting ice is opening up the Arctic
As global climate change melts the sea ice that covers the Arctic Ocean, new shipping lanes are opening and nations and companies are jockeying for positon, hoping to stake claim to oil and gas deposits that lie beneath the seafloor
Risky

We are exploiting new fossil fuel sources such as oil sands
Three sources of "unconventional" fossil fuels (oil sands, oil shale, and methane hydrate) are abundant and together could theoretically supply our civilization for centuries
However, they are difficult and expensive to extract and process
Also their net energy values and EROI ratios are very low
Extracting oil sands and oil shale consumes large volumes of water, ruins landscapes, and pollutes waterways
Burning these fossil fuels would likely emit more greenhouse gases than our use of coal, oil, and natural gas currently does, worsening air pollution and climate change
Emissions pollute air and drive climate change
Clean coal technologies aim to reduce air pollution from coal
Clean coal technologies: refer to techniques, equipment, and approaches that aim to remove chemical containments during the generation of electricity from coal at power plants.
Another approach is to dry coal that has high water content, making it burn cleaner
Gasification: coal is converted into a cleaner synthesis gas (syngas) by reacting it with oxygen and steam at a high temperature
We gain more power from coal with less pollution
Syngas from coal can be used to turn a gas turbine or to heat water to turn a steam turbine
Can we capture and store carbon?
Carbon capture: technologies or approaches that remove carbon dioxide from power plant or other emissions, in a effort to mitigate global climate change
Carbon storage/ carbon sequestration: technologies or approaches to sequester, or store, carbon dioxide from industrial emissions (eg. underground under pressure in locations where it will not seep out) in an effort to mitigate global climate change. The term can also refer to the natural sequestration of carbon by plants through photosynthesis
Carbon capture and storage is being attempted at a variety of facilities
At the present carbon capture and storage is too unproven to be the central focus of a clean energy strategy
We all pay external costs
Fossil fuel extraction has mixed consequences for local people
Wherever fossil fuels are extracted, people living nearby must weigh the environmental, health, and social drawbacks of extractive development against the financial benefits they may gain
Communities where fossil fuels extraction takes place, they experience high-paying jobs and economic activity and for many people these benefits outweigh other concerns
Eminent domain: a policy in which a government pay landowners for their land at market rates and the landowners have no recourse to refuse. In eminent domain, court set aside private property rights to make way for projects judged to be for the public good
Dependence on foreign energy affects the economies of nations
Virtually all of our modern technologies and services depend somehow on fossil fuels
We are vulnerable to supplies becoming costly or unavailable
Nations with few fossil fuels reserves of their own are especially vulnerable
Reliance means that seller nations can control energy prices, forcing buyer nations to pay more as supplies dwindle
Energy efficiency and conservation
Efficiency and conservation bring benefits
Energy efficiency: describes the ability to obtain a given amount of output while using less energy input
Energy conservation: describes the practice of reducing wasteful or unnecessary energy use
Efficiency results from technological improvements, whereas conservation stems from behavioral choices
Greater efficiency allows us to reduce energy use, efficiency is a primary means of conservation
Efficiency and conservation help us to waste less and to reduce our environmental impact
Extends the lifetime of nonrenewable energy supplies
Personal choice and efficient technologies are two ways to conserve
We can make conscious choices to reduce our energy consumption by driving less, dialing down thermostats, turning off lights, and cutting back on machinery
As a society we can conserve energy by developing technologies and strategies to make devices and processes more efficient
One way we can improve the efficiency of power plants is through cogeneration: a practice in which the extra heat generated in the production of electricity is captured and put to use heating workplaces and homes, as well as producing other kinds of power
Cogeneration can almost double the efficiency of a power plant
Automobile fuel efficiency is a key to conservation
A mandate to increase the mile per gallon fuel efficiency of cars
Corporate Average Fuel Efficiency (CAFÉ): sets benchmarks for auto manufacturers to meet.
The rebound effect cuts into efficiency gains
Gains in efficiency from better technology may be partly offset if people engage in more energy-consuming behaviors as a result
Rebound effect: the phenomenon by which gains of efficiency from better technology are partly offset when people engage in more energy-consuming behavior as a result. This common psychological effect can hamper conservation and efficiency efforts
Driving your fuel efficient car more than what you usually did with your old car
Nuclear Power
Fission releases nuclear energy in reactors to generate electricity
Nuclear Energy: the energy that holds together protons and neutrons in the nucleus of an atom.
We harness this energy by converting it to thermal energy inside nuclear reactors: facilities contained within nuclear power plants.
This thermal energy is then used to generate electricity by turning turbines with steam
Nuclear fission: The reaction that drives the release of nuclear energy inside nuclear reactors; the splitting apart of atomic nuclei
In fission, the nuclei of large heavy atoms are bombarded with neutrons
Nuclear energy comes from processed and enriched uranium
We use the element uranium for nuclear power because its atoms are radioactive, emitting subatomic particles and high-energy radiation as they decay into a series of daughter isotopes
Nuclear power delivers clean energy
Using fission, nuclear power plants generate electricity without creating the air pollution that fossil fuels do
The power-generating process is essentially emission-free
Advantages
Nuclear power poses far fewer chronic health risks from pollutants
Generates far more power than coals
Disadvantages
Arranging the safe disposal of radioactive waste is challenging
If an accident occurs at a power plant, the consequences can potentially be catastrophic
Nuclear power poses small risks of large accidents
Three Mile Island
A combo of mechianical failure and human error caused coolant water to drain from the reacter vessel, temperatures to rise inside the reactors core
Chernobyl
Fukushima Daiichi
Waste disposal remains a challenge
Nuclear power's growth has slowed
homework
The United States and other industrialized nations devote the greatest proportion of their oil use to __________. Transportation
What is the difference between EROI (energy returned on investment) and net energy? Net energy is simply the difference between energy returned and energy invested. EROI is a ratio with energy return in the numerator and energy invested in the denominator.
Which of the fossil fuels is most abundant on Earth? Coal
The process of __________ turns crude oil into the type of gases that can be used for cooking, in cars, and for other human purposes. Redefining
Plant-based organic matter that is compressed under high pressure to form solid carbon structures is known as __________. coal


What is Hubbert's peak? a prediction, based on rates of extraction and new discovery, of when a country's or global oil production will be at a maximum and then start to fall
Which fossil fuel is produced as a by-product that occurs when bacteria decompose organic material under anaerobic conditions? Methane
Many pollutants from coal-fired power plants are properly managed today. Which of the following is currently considered to be the biggest threat to the environment? Carbon dioxide
All fossil fuels, including coal, are considered an indirect form of ____________ energy. Solar
Where is electricity made at a coal-fired power plant? generator
During peak usage, what happens to the cost of electricity? It almost always increases
What color smoke coming from a coal-fired power plant would indicate wasted fuel? black
Which of the following countries exports the most oil to the United States? Canada

What compound that results from hydraulic fracturing gives rise to air pollution? Methane
How is the energy produced by nuclear fission used to produce electricity? Water in the containment vessel is kept under high pressure and heat from the fission reactions that heat it to well over boiling. This is then used to boil another loop of water, which turns a turbine that drives a generator and makes electricity.
Which of the following is one of the biggest problems with nuclear power? Radioactive waste
Which of the following statements accurately describes nuclear fusion reactors? Fusion reactions require very high temperatures
Which of the following individuals is most likely to support fracking? An executive for the Western States Petroleum Association.
In California, why do most energy companies choose to use fresh water for fracking as opposed to brackish water? Fresh water is typically cheaper
Your aunt worked diligently to help get the most stringent laws against fracking passed in her state. Where does she live? Vermont
You are a mechanical engineer for C & J Energy Services, working on an idea to safely frack the Monterey Shale. What is the biggest obstacle for you to overcome? The geology of the region
You are an environmental activist in Texas and wish to promote an anti-fracking bill. You decide to use the same unique focus as that being used in California. What are you focusing on? The intense use of water
Ch16 Alternatives to Fossil Fuel
Conservation
Nuclear
Renewables
How will we convert to renewable energy?
Fossil fuel supplies are limited and their use has consequences
Nations have several options for future energy use
Continue relying on fossil fuels until they are no longer available
Increase funding to develop alternative energy sources dramatically
Steer a middle course and gradually reduce our reliance on fossil fuels
Our reliance on fossil fuels has consequences
Transition should begin soon
Technological and economic barriers prevent rapid switch
Renewables receive little government help
Need infrastructure for renewables
Companies are unwilling to rapidly change
Transitioning too slowly will cause disrupted economies and a degraded environment
Conventional Alternatives
Nuclear Hydroelectric Biomass
Conventional alternatives
Alternative energy sources currently the most developed and most widely used:
nuclear energy, hydroelectric power, and energy from biomass
These are all "conventional alternatives" to fossil fuels
They exert less environmental impact
These are best viewed as intermediates along a continuum of renewability
Nuclear Power
The U.S. generates the greatest amount of nuclear power
20% of U.S. electricity comes from nuclear sources
France receives the highest proportion of its electricity from nuclear power (78%)
Figure 15.18 Labeled
Figure 15.19 Labeled
Figure 15.21 Labeled
Figure 15.22 Labeled
Coal versus nuclear power
Waste disposal remains a problem
The long half-lives of radioisotopes = emitting radiation for thousands of years
Radioactive waste must be placed in unusually stable and secure locations where radioactivity will not harm future generations
Spent fuel rods must be stored
Spent fuel rods are sunk in pools of cooling water to minimize radiation leakage
By 2010, 75% of U.S. plants will have no room left for this type of storage
They are now expanding their storage capacity through dry storage
U.S. stores tons of waste
U.S. power plants store 56,000 metric tons of high-level radioactive waste, as well as much more low-level radioactive waste
Waste is held at 125 sites in over 39 states
Over 161 million U.S. citizens live within 75 miles of temporarily stored waste
Yucca Mountain waste repository
First suggested in 1978
Under geological stable rock formation in Nevada
Planned to receive waste for permanent storage
Funding cancelled in 2011 by Federal government
Currently no long term storage available or planned
Storage of high-level radioactive waste

Biomass Fuels
Figure 16.4 Labeled
Biomass fuels
Biomass sources include a variety of materials
Biopower = produced when biomass sources are burned in power plants, generating heat and electricity
Biofuels = biomass sources converted into fuels to power automobiles
Biofuels can power automobiles
Ethanol = produces as a biofuel by fermentation
Ethanol is widely added to U.S. gasoline to reduce emissions
Any vehicle will run well on a 10% ethanol mix
A primary biofuel
Biofuels can power vehicles
Biodiesel: a fuel produced from vegetable oil, used cooking grease, or animal fat
This oil or fat is mixed with small amounts of ethanol or methanol in the presence of chemical catalyst
Biodiesel's fuel economy is nearly as good, it costs just slightly more
It is nontoxic and biodegradable
Novel biofuels
Cellulosic ethanol: ethanol produced from the cellulose in plant tissues by treating it with enzymes. Techniques for producing cellulosic ethanol are under development because of the desire to make ethanol from low-value crop waste (residue such as corn stalks and husks), rather than from the sugars of high-value crops
Cars can run on ethanol
Flexible fuel vehicles = run on 85% ethanol
But, very few gas stations offer this fuel
Researchers are refining techniques to produce ethanol from cellulose, so ethanol could be made from low-value crops, instead of high-value crops
The Ethanol Dilemma
Current production methods rely on food crops

Correlated effects
food production
global hunger
Biodiesel is produced from vegetable oil
U.S. biodiesel producers use soybean oil
Animal fats, used grease, and cooking oil can also be used
Vehicles can run on 100% biodiesel, but the engine needs to be modified
Biodiesel cuts down on emissions; its fuel economy is almost as good and costs slightly more than gasoline
Alternative biofuel sources
Hydroelectric Power
Hydroelectric power
The generation of electricity using kinetic energy of moving water
Uses kinetic energy of moving water
Harness energy by storing water in reservoirs behind dams

Hydropower accounts for 2.2% of the world's energy supply
And 16% of the world's electricity production
A typical dam
A run-of-river system
Hydroelectric power is widely used
Hydropower accounts for 2.2% of the world's energy supply
And 16% of the world's electricity production
Nations with large rivers and economic resources have used dams
However, many countries have dammed their large rivers
Hydropower uses three approaches
Most hydroelectric power today comes from impounding water in reservoirs behind concrete dams that block the flow of river water and then letting the water pass through the dam.
Because water is stored behind dams, this is called the storage technique
The run-of-river technique: generates electricity without greatly disrupting a river's flow
Method one: divert a portion of a river's flow through a pipe or channel, passing it through a powerhouse and returning it to the river
Pumped Storage: to better control the timing of flow. Water is pumped from a lower reservoir to a higher reservoir at times when demand for power is weak and prices are low
Hydropower is clean
Two clear advantages over fossil fuels for producing electricity:
It is renewable: as long as precipitation fills rivers we can use water to turn turbines
It is clean: no carbon dioxide is emitted
Hydropower is efficient
It has an EROI of 10:1, as high as any modern-day energy source
Hydropower's negative impacts
Damming rivers destroys habitats
Upstream areas are submerged
Downstream areas are starved of water
Natural flooding cycles are disrupted
Thermal pollution of downstream water
Periodic flushes of cold reservoir water can kill fish
Dams block passage of fish
fragmenting the river and reducing biodiversity
Hydropower may not expand much more
Most of the world's large rivers have already been dammed
China's Three Gorges Dam is the world's largest dam; suboptimal site
People have grown aware of the ecological impact of dams
Developing nations will probably increase hydropower if they have rivers
Bioenergy
Bioenergy/ biomass energy: energy obtained from biomass
Biomass: consists of organic material derived from living or recently organisms and it contains chemical energy that originated with sunlight and photosynthesis
We harness bioenergy by burning biomass for heating, using biomass to generate electricity and processing biomass to create liquid fuels for transportation
The New Renwables
Solar Wind Geothermal Wave Power
"New" renewable energy sources
"New" renewables are a group of alternative energy sources that include
Energy from the Sun, wind, geothermal heat, and movement of the ocean water
They are commonly referred to as "new" because:
They are not yet used on a wide scale
Their technologies are still in a rapid phase of development
They will play a much larger role in our energy use in the future
New renewables provide little of our power
The new renewables are growing fast
Advantages of new renewables
Benefits of the new renewables include:
Alleviate air pollution and greenhouse gas emissions
They are inexhaustible, unlike fossil fuels
Diversify a country's energy economy
Create jobs and are sources of income and taxes, especially in rural areas
Green-collar jobs: jobs that design, install, maintain, and manage the development of technologies and rebuild and operate society's energy infrastructure
New energy sources create jobs
New technologies require more labor per unit of energy output
More jobs will be generated than remaining with a fossil fuel economy
Rapid growth will continue as:
Population and consumption grow, energy demand increases, fossil fuel supplies decline, and people demand a cleaner environment
Solar energy
Energy from the sun
Sun provides energy for almost all biological activity on Earth
Each square meter of Earth receives about 1 kilowatt of solar energy = 17 times more than a lightbulb
Active vs. Passive Solar
Passive solar energy
the most common way to harness solar energy
Buildings are designed to maximize direct absorption of sunlight in winter and keep cool in summer
Active solar energy collection
uses technology to focus, move, or store solar energy
Generally consists of dark, heat-absorbing metal plates mounted on rooftops in flat glass-covered boxes

Passive solar heating is simple and effective
Low south-facing windows maximize heat in the winter
Overhangs on windows block light from above in the summer
Thermal mass = construction materials that absorb, store, and release heat
Planting vegetation in strategic locations
By heating buildings in winter and cooling them in summer, passive solar methods conserve energy and reduce costs
Active solar energy collection
Flat plate solar collectors (solar panels) = one active method for harnessing solar energy
Installed on rooftops
Dark-colored, heat-absorbing metal plates
Water, air, or antifreeze pass through the collectors, transferring heat throughout the building
Heated water is stored and used later
Figure 16.9 Labeled
Concentrating Sunlight Focuses Energy
We can harness energy from sunlight to produce electricity at concentrated solar power plants.
Concentrated Solar Energy: a means of generating electricity at a large area (like a large centralized facilities) onto a smaller area (like homes or businesses). Several approaches are used.
Method One: curved mirrors focus sunlight onto synthetic oil in pipes. The superheated oil is piped to a facility where it heats water, creating steam that drives turbines to generate electricity
Method Two: hundreds of mirrors focus sunlight onto a central receiver atop a tall power tower. From there, air or fluids carry heat through pipes to steam-driven generator
Solar energy use is increasing
1.5 million homes and businesses heat water with solar panels, mostly for swimming pools
Solar panels are used far from any sort of electrical grid to help boil water and power rural hospitals
Solar power need not be expensive or in regions that are always sunny
Concentrating solar rays magnifies energy
Solar cookers = simple, portable ovens that use reflectors to focus sunlight onto food
Power tower = mirrors concentrate sunlight onto receivers to create electricity
Solar-trough systems = mirrors focus sunlight on oil in troughs
Superheated oil creates steam to produce electricity
Photovoltaic cells generate electricity
Photovoltaic cells = collect sunlight and convert it into electrical energy
It converts sunlight to electrical energy when light strikes one of a pair of plates made primarily of silicon, a semiconductor that conducts electricity
These are used with wind turbines and diesel engines
Photovoltaic (photoelectric) effect = occurs when light strikes one of a pair of metal plates in a PV cell, causing the release of electrons, creating an electric current
Thin-film solar photovoltaic materials compressed into ultra-thin sheets
Less efficient as converting sunlight to electricity but cheaper to produce
Net metering process by which homeowners or business with photovoltaic systems or wind turbines can see their excess solar energy or wind power to their local utility. Whereas feed-in-tariffs award producers with prices about the market rates, net metering offers market-rate prices
A typical photovoltaic cell
Solar power is little used but fast growing
Solar energy was pushed to the sidelines as fossil fuels dominated our economy
Funding for research and development erratic
Because of a lack of investment, solar energy contributes only a miniscule amount of energy
Solar energy is attractive in developing nations
Hundreds of millions don't have electricity
Some multinational companies are investing in solar energy
Solar energy will continue to grow
Solar energy use should increase
As prices fall, technologies improve and governments enact economic incentives
Japan and Germany lead the world in PV installation
The U.S. may recover its leadership, given a 2005 federal tax credit and some state initiatives
Solar power offers many benefits
The Sun will burn for 4 - 5 billion more years
Solar technologies are quiet, safe, use no fuels, contain no moving parts, and require little maintenance
They allow local, decentralized control over power
Solar power does not emit greenhouse gases and air pollution
Developing nations can use solar cookers, instead of gathering firewood
Net metering = PV owners can sell excess electricity to their local power utility
Variable insolation is a drawback
Not all regions are sunny enough to provide enough power, with current technology
Daily and seasonal variation also poses problems
Storage of energy becomes key
Batteries, hydrogen, ...?

Cost is a drawback
Up-front costs are high
Solar power remains the most expensive way to produce electricity
The government has subsidized fossil fuels and nuclear energy at the expense of solar energy

Wind has long been used for energy
Wind Power: a source of renewable energy, in which kinetic energy from the passage of wind through wind turbines is used to generate electricity
Wind turbines = devices that harness power from wind
A mechanical assembly that converts the wind's kinetic energy, or energy of motion, into electrical energy
Windmills have been used for 800 years to pump water
The first windmill to generate electricity was built in the late 1800s
After the 1973 oil embargo, governments funded research and development
Today, wind power produces electricity for the same price as conventional sources
Modern wind turbines
Wind blowing into a turbine turns the blades of the rotor, which rotate machinery inside a compartment (nacelle) on top of a tall tower
Wind farms
Turbines erected in groups of up to hundreds of turbines
Turbines harness wind as efficiently as possible
Different turbines turn at different speeds
Slight increases in wind velocity yield significant power output
Wind is the fastest-growing energy sector
Wind power grew 25% per year globally between 2000 and 2005
Five nations account for 80% of the world's wind power
California and Texas produce the most wind power in the U.S.
Wind power could be expanded to meet the electrical needs of the entire U.S.
Offshore sites can be promising
Costs to erect and maintain turbines in water are higher, but the stronger, less turbulent winds produce more power and make offshore wind more profitable
Wind speeds are 20% greater over water than over land
There is less air turbulence over water than land
Currently, turbines are limited to shallow water
Wind power has many benefits
Wind produces no emissions once installed
It prevents the release of CO2
It is more efficient than conventional power sources
Turbines also use less water than conventional power plants
Farmers and ranchers can lease their land
Produces extra revenue
Landowners can still use their land for other uses
Advancing technology is also driving down the cost of wind farm construction
Wind power downsides
We have no control over when wind will occur
Good wind sources are not always near population centers that need energy
NIMBY
Wind turbines pose a (very minor) threat to birds and bats
Geothermal energy
Geothermal energy: is thermal energy that arises from beneath Earth's surface
Radioactive decay of elements under extremely high pressures deep inside the planet generates heat
This heat rises through magma, fissures, and cracks
Geothermal power plants use heated water and steam for direct heating and generating electricity
The origins of geothermal energy
Geothermal energy produces heat and electricity
Most often wells are drilled hundreds or thousands of meters toward heated groundwater
Water at temperatures of 150 - 370 degrees Celsius is brought to the surface and converted to steam, which turns turbines that generate electricity
Hot groundwater can be used directly to heat buildings
Cheap and efficient

Geothermal energy is renewable in principle
But if a geothermal plant uses heated water faster than groundwater is recharged, the plant will run out of water
Operators have begun injecting municipal wastewater into the ground to replenish the supply
Patterns of geothermal activity shift naturally
An area that produces hot groundwater now may not always do so
Geothermal energy is greatest in the west
Heat pumps are highly efficient
Geothermal ground source heat pumps (GSHPs) use thermal energy from near-surface sources of earth and water
The pumps heat buildings in the winter by transferring heat from the ground into buildings
In the summer, heat is transferred through underground pipes from the building into the ground
Highly efficient, because heat is simply moved
Currently installed on campus (JCC)
Figure 16.22 Labeled
Use of geothermal power is growing
Currently, geothermal energy provides less than 0.5% of the total energy used worldwide
It provides more power than solar and wind combined
But, much less than hydropower and biomass
Geothermal energy in the U.S. provides enough power to supply electricity to more than 4 million people
The U.S., Japan, and China lead the world in geothermal power use
Geothermal power has benefits and limits
Benefits:
Reduces emissions
It does emit very small amounts of gases
Limitations:
May not be sustainable
Water is laced with salts and minerals that corrode equipment and pollute the air
Limited to areas where the energy can be trapped
Restricted to areas where we can tap energy from naturally heated groundwater
To help solve this problem -> Enhanced geothermal systems (EGS): a new approach whereby engineers drill deeply into rock, fracture it, pump in water, and then pump it out once it is heated below ground. This approach would enable us to obtain geothermal energy in many locations
Tidal energy from the oceans
Tidal energy: energy harnessed by erecting a dam across the outlet of a tidal basin. Water flowing with the incoming or outgoing tide through sluices in the dam turns turbines to generate electricity
The rising and falling of ocean tides twice each day throughout the world moves large amounts of water
Differences in height between low and high tides are especially great in long narrow bays
These areas are best for harnessing tidal energy by erecting dams across the outlets of tidal basins

Wave energy
Wave energy: energy harnessed from the motion of ocean waves. Many designs for machinery to harness wave energy has been invented, but few have been adequately tested
Can be developed at a greater variety of sites than tidal energy
The motion of wind-driven waves at the ocean's surface is harnessed and converted from mechanical energy into electricity
Many designs exist, but few are adequately tested
Some designs are for offshore facilities and involve floating devices that move up and down the waves
Wave energy is greater at deep ocean sites, but transmitting electricity to shore is very expensive
Figure 16.23 Labeled
Coastal onshore facilities
Waves are directed into narrow channels and elevated reservoirs; electricity is generated when water flows out
Another design uses rising and falling waves to push air in and out of chambers, turning turbines to generate electricity
No commercial wave energy facilities are operating
A third design uses the motion of ocean currents, such as the Gulf Stream
Currently being tested in Europe
Ocean thermal energy
Ocean thermal energy conversion (OTEC) a potential energy sources that involves harnessing the solar radiation absorbed by tropical ocean water
Each day, the tropical oceans absorb an amount of solar radiation equal to the heat content of 250 bbl
The ocean's surface is warmer than deep water
Ocean thermal energy conversion (OTEC) is based on this gradient in temperature
Costs remain high and no facility is commercially operational
What about hydrogen?
Is a switch to H from C feasible?
Hydrogen economy
The development of fuel cells and hydrogen fuel shows promise to store energy in considerable quantities
To produce clean, efficient electricity
A hydrogen economy would provide a clean, safe, and efficient energy system
By using the world's simplest and most abundant element as fuel
Hydrogen economy
Electricity generated from renewable sources could be used to produce hydrogen
Vehicles, computers, cell phones, home heating, and countless other applications could be powered
Basing an energy system on hydrogen could alleviate dependence on foreign fuels and help fight climate change
A typical hydrogen fuel cell
A hydrogen-fueled bus
Production of hydrogen fuel
Electrolysis = electricity is input to split hydrogen atoms from the oxygen atoms of water molecules:

2H2O 2H2 + O2

Produces pure hydrogen
Will cause some pollution depending on the source of electricity, but less than than other processes
Other ways of obtaining hydrogen
Hydrogen can also be obtained from biomass and fossil fuels, such as methane (CH4)

CH4 + 2H2O 4H2 + CO2

Results in emissions of carbon-based pollution
Fuel cells produce electricity
Once isolated, hydrogen gas can be used as a fuel to produce electricity within fuel cells
The chemical reaction involved in that fuel cell is the reverse of electrolysis
2H2 + O2 2H2O
The movement of the hydrogen's electrons from one electrode to the other creates electricity
Hydrogen and fuel cells have many benefits
We will never run out
hydrogen is the most abundant element in the universe
Can be clean and nontoxic to use
May produce few greenhouse gases and other pollutants
Can be no more dangerous than gasoline in tanks
Cells are energy efficient
Conclusions
Fossil Fuels, Nuclear, New and Old Alternatives
Conclusions
Fossil fuels have helped us build our complex industrialized societies
We are now approaching a turning point in history: fossil fuel production will begin to decline

All energy comes from the sun...
...but not all sources are sustainable
Peak oil and the increasing concern over global climate change have convinced many to shift to renewable energy
homework
Which of these is a major reason that we have used fossil fuels rather than their alternatives? Market costs are generally lower for fossil fuels than for their alternatives.
Why is renewable energy use growing? There is increasing concern over the environmental impacts of fossil fuel combustion.
How is the sun's energy production different from the process in which energy is produced in current nuclear power plants? The sun releases energy through nuclear fusion, whereas our current nuclear power technology releases energy through nuclear fission.


Passive solar energy collection includes which of the following technologies? buildings designed and building materials chosen to maximize their direct absorption of sunlight
Which of these statements is NOT true of wind power? Wind turbines take up large amounts of land that is then unsuitable for other purposes.
What sort of threat does wind energy pose to certain kinds of wildlife? Flying creatures such as birds and bats are killed when they fly into wind turbine blades.

The ultimate source of energy that drives wind power is __________. The sun
A typical wind farm in the United States consists of __________. many very large wind turbines clustered in a region with a low human population
The year 2030 goal set by the US Department of Energy is to generate __________. 20% of electricity using wind-powered systems
Electricity in a wind turbine is generated __________. when spinning magnets move past a coil of copper wire
Producing electricity using wind instead of fossil fuels__________. generates no carbon dioxide in the process
What is the ultimate source for geothermal energy? the radioactive decay of elements deep within Earth

Which of the following statements is NOT accurate regarding geothermal power? Geothermal power generators are one of the true fully sustainable energy sources.
Ocean thermal energy conversion (OTEC) is NOT being used for energy generation anywhere right now. Why not? The cost of generating energy is much too high for OTEC to make economic sense.
Why is there little to no growth expected for hydropower? Almost all rivers that can be dammed for power generation have been dammed already.
What is the ultimate energy source for biomass (also known as biomass energy)? sunlight through the process of photosynthesis, in which the chemical potential energy of biomass originates
Which of the following statements about ethanol is true? Growing corn for ethanol requires substantial inputs of fossil fuel energy.

What is electrolysis? the splitting of water into component hydrogen and oxygen
What two waste products are produced by hydrogen fuel cells? Water and heat
Environmental Hazards and Risk Assessment
Physical, cultural, biological, and chemical hazards
Environmental toxicology and methodology
Environmental Health
Assesses environmental factors that influence human health and quality of life
Considers both natural and human-caused factors
(Does not traditionally take an ecological systems perspective...)
Environmental hazards
Physical = natural earth processes
Physical hazards arise from processes that occur naturally in our environment and pose risks to human life or health
Examples
Excessive exposure to UV radiation
Earthquakes
Volcanoes
Fires
Floods
Droughts...
We cannot prevent many of these hazards, but we can minimize risk by preparing by practicing emergency plans and avoiding unsafe practices
Environmental hazards
Biological = result from ecological interactions among organisms
Viruses, bacteria, and other pathogens
When we get sick from a virus, bacterial infection, or other pathogen, we are suffering parasitism
Infectious (communicable, or transmissible) disease
A disease in which a pathogen attacks a host
Predation (rare)
This includes animals
Disease is a major focus of environmental health
Infectious disease
Infectious disease
Many emerging/ persistent diseases
MDR tuberculosis,
HIV,
West Nile virus
Key factors
mobility
evolving resistance to antibiotics
climate change
will expand the range of diseases
Environmental hazards
Cultural = result from the place we live, our socioeconomic status, our occupation, our behavioral choices
We can sometimes minimize other times it is outside our control
Smoking
Drug use
Diet and nutrition
Crime
Mode of transportation
Environmental Hazards
Chemical = synthetic or natural compounds that can affect human health
Some natural substances that we process for our use (such as hydrocarbons, lead, and asbestos) are also harmful to human health
Benzene
Criteria air pollutants
Urushiol
Emissions of microbial metabolism...
Natural vs. synthetic?
Chemical toxicants also exist naturally and in our food
Some scientists believe exposure to natural toxicants dwarfs that of synthetics
Others point out natural toxins are more readily metabolized and excreted
Key: synthetic chemicals more likely to persist and accumulate
Why?
Disease and Toxicology
Disease causes the vast majority of human deaths worldwide.
Noninfectious disease: not spread from person to person, but influenced by genetics, environmental factors, and lifestyle choices.
Toxicology is the study of chemical hazards
Toxicology is the science that examines how poisonous chemicals affect the health of humans and other organisms
Toxicity: toxicology assess and compare substances to see the degree of harm a chemical substance can inflict
Toxicant: a toxic substances, or poison
Environmental toxicology: toxic substances that come from or are discharged into the environment
Toxin: toxic chemicals manufactured in the tissues of living organisms
Many environmental health hazards exists indoors
Cigarette smoke
Radon
Lead poisoning
Polybrominated diphenyl ethers (PBDEs)
In fire retardant computers, TVs, plastics, and furniture that can slowly evaporate throughout the lifetime of the product
PBDEs

Polybrominated diphenyl ethers = fire-retardent properties
Used in computers, televisions, plastics, and furniture
Persist and accumulate in living tissue
Endocrine disruptor = mimic hormones and interfere with the functioning of animals' endocrine (hormone) systems
Toxicology
Study of the effects of poisonous substances on humans and other organisms
Toxicity = the degree of harm a toxicant can cause
"The dose makes the poison"
Toxicant = a toxic agent
Environmental toxicology
Study of toxic substances that come from or are discharged into the environment
Studies the health effects on humans, other animals, and ecosystems
Focus mainly on humans, using other animals as test subjects
Environmental toxicants
The environment contains natural chemicals that may pose health risks
Synthetic chemicals are increasing in concentration in the environment
Environmental toxicants
Categories of toxicants
Carcinogens = cause cancer
Mutagens = cause DNA mutations
Can lead to severe problems, including cancer
Teratogens = cause birth defects
Allergens = overactivate the immune system causing an immune response when one is not necessary
Neurotoxins = assault the nervous system
Endocrine disruptors = interfere with the endocrine (hormone) system
Pathway inhibitors= toxicants that interrupt vital biochemical processes in organisms by blocking one or more steps in important biochemical pathways.

Silent Spring and synthetic toxicants
In the 1960s, pesticides were mostly untested and were sprayed over public areas, assuming they would do no harm
Silent Spring by Rachel Carson (1962)
Brought together studies to show DDT risks to people, wildlife, and ecosystems
The book generated significant social change
Exposure
Acute exposure: a person experiences high exposure for short periods of time
Discrete events
Accidental ingestion
Oil spill
Chemical spill
Nuclear accident
Chronic exposure: low exposure over a long period of time
Affect organs
Smoking
Alcohol abuse
Toxic Substance and Their Effect on Ecosystem
Some toxicants persist in environment
Breakdown product: when toxic substances degraded into simpler compounds. These are less harmful than the original substances, but sometimes they are just as toxic as the original chemical
Bioaccumulation/Biomagnification
Fat-soluble toxicants are stored in fatty tissues
Bioaccumulation = toxicants build up in animal tissues
Biomagnification = concentrate in top predators
Yaqui Valley pesticide study
Endocrine disruption toxic substances that interfere with the endocrine system. The endocrine system consists of hormones that travel through the bloodstream at low concentrations and perform many vital functions
Theo Colburn wrote Our Stolen Future in 1996
Synthetic chemicals may be altering the hormones of animals
This book integrated scientific work from various fields
Shocked many readers and brought criticism from the chemical industry
Endocrine disruption
Endocrine disruption
Frogs with gonadal abnormalities
Male frogs feminized from atrazine at concentrations far below EPA guidelines
PCB-contaminated human babies were born weighing less, with smaller heads
Studying Effects of Hazards
Human studies rely on case histories, epidemiology and animal testing
Case history: the process of observing and analyzing individual patients that sickened.
Epidemiological studies: large scale comparisons among groups of people usually contrasting a group known to have been exposed to some hazard against a group that has not
Epidemiological studies track the fate of all people in the study for a long period of time (years, decades) and measure the rate at which death, cancer, or other health problems occur in the group
Dose-response analysis is a mainstay of toxicology
Dose-response analysis: the standard method of testing with lab animals in toxicology
Scientist quantify the toxicity of a substance by measuring the strength of its effects or the number of animals affected at different doses.
Dose: the amount of substance the test animal receives
Response: the type or magnitude of negative effects the animal exhibits as a result
Dose-response curve: the data plotted on a graph with does on the x-axis and response on the y-axis
Threshold: when responses can only occur above a certain dose
Chemical mixes may be more than the sum of their parts
Synergistic effects: interactive impacts that are greater that the simple sum of their constituent effects
Endocrine disruption
Endocrine disruption
Research results are uncertain, which is inherent in any young field
Negative findings pose economic threats to chemical manufacturers
Banning a top-selling chemical could cost a company millions of dollars
Bisphenol-A (BPA), found in plastics, can cause birth defects, but the plastics industry protests that the chemical is safe
Studies reporting harm are publicly funded, but those reporting no harm are industry funded
Risk assessment the quantitative measurement of risk and the comparison of risks involved in different activities or substances together. It is a way to identify and outline problems
Risk = the probability that some harmful outcome will result from a given action
Exposure causes some probability (likelihood) of harm
Probability entails
Identity and strength of threat
Chance and frequency that an organism will encounter it
Amount of exposure to the threat
Sensitivity to the threat
Perceiving risks
Everything we do involves some risk
We try to minimize risk, but we often misperceive it
Flying versus driving
We feel more at risk when we cannot control a situation
We fear nuclear power and toxic waste, but not smoking or overeating
Risk Perception Activity
In groups, discuss the sources of mortality on the form
Reach a consensus on the rankings for this set of hazards
Report out your ranks for the top 5 hazards
Actual risks in U.S.
Risk management decisions and strategies to minimize risk. Scientific assessments of risk are considered in light of economic, social, and political needs and values
Current US approach
Innocent until proven guilty: product assumed safe after limited testing
Benefits: technological innovation and economic advancement
Disadvantage: putting into wide use some substances that may later on turn out to be dangerous
European approach
Precautionary principle: extensive testing required to prove a product is safe
Assume substances are harmful until they are proven harmless
Identifies troublesome toxicants before they are released
But, this may impede the pace of technology and economic advance

US Federal Agencies
Federal agencies apportion responsibility for tracking and regulating synthetic chemicals
FDA: food, food additives, cosmetics, drugs, and medical devices
EPA: pesticides
Occupational Safety and Health Administration (OSHA): workplace hazards
Many public health and environmental advocates fear it isn't enough
Many synthetic chemicals are not actually tested
Only 10% have been tested for toxicity
Fewer than 1% are government regulated
International regulation
Stockholm Convention on Persistent Organic Pollutants (POPs) ratified by 140 nations in 2004
Ends the release of the 12 most dangerous POPs

International regulation
EU's Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH) Program
Aims to evaluate and restrict dangerous chemicals while giving industries a streamlined regulatory system
Cost to chemical industry 2.8-5.2 billion euros ($3.8-7.0 billion)
Savings estimated more than 10 times that in health benefits—but to government and insurance
Conclusion
International agreements represent a hopeful sign that governments are working to protect society, wildlife, and ecosystems from toxic chemicals and environmental hazards
Once all the scientific results are in, society's philosophical approach to risk management will determine what policies are enacted
A safe and happy future depends on knowing the risks that some hazards pose and on replacing those substances with safer ones
Waste and Waste Management
Types of waste
Approaches to waste
Hazardous waste
Lecture Goals
Types of waste
Approaches to managing waste
Conventional waste disposal methods
Ways to reduce waste
Industrial solid waste management
Issues in managing hazardous waste

Waste
Waste = any unwanted material or substance that results from human activity or process
Municipal solid waste (MSW)= non-liquid waste that comes from homes, institutions, and small businesses
Industrial solid waste = waste from production of consumer goods, mining, agriculture, and petroleum extraction and refining
Waste
Waste (cont.)
Hazardous waste =solid or liquid waste that is toxic, chemically reactive, flammable, or corrosive
Wastewater = water used in a household, business, or industry, as well as polluted runoff from our streets and storm drains
Waste management
Ranking three pathways of waste management:
Minimizing the amount of waste we generate (source reduction)
Recovering waste materials and finding ways to recycle them
Disposing of waste safely and effectively
Waste management
Waste stream = flow of waste as it moves from its sources toward disposal destinations
More efficient use of materials, consume less, buy goods with less packaging, reusing goods
Source reduction: minimizing waste at its source
Recovery (recycling, composting) = reclaiming materials with some value
Recycling = sends used goods to manufacture new goods
Composting = recovery of organic waste
Municipal Solid Waste in the US
Municipal solid waste (MSW)
In the U.S., paper, yard debris, food scraps, and plastics are the principal components of municipal solid waste
Even after recycling, paper is the largest component of solid waste
Most waste comes from packaging
In developing countries, food scraps are the primary contributor
Waste generation in the US
Waste generation in the US
Waste generation in the U.S.
In the U.S. since 1960, waste generation has increased 2.8 times

What's in there?
Check and see...
Waste generation in developing nations
Consumption increasing in developing nations
Rising material standard of living
More packaging
Scavenger Economy
Locally wealthy consumers often discard items that can still be used
Landfill disposal methods
Historically, open dumping and burning
...and still occurs throughout the world
Most industrialized nations now use landfills or incineration facilities

Sanitary landfills
Sanitary landfills = waste buried in the ground or piled in large, engineered mounds
Must meet national standards set by the EPA under the Resource Conservation and Recovery Act (RCRA) of 1976

Waste is partially decomposed by bacteria and compresses under its own weight to make more space
Layered with soil to reduce odor, speed decomposition, reduce infestation by pets
When a landfill is closed, it must be capped and maintained
Landfills can produce gas for energy
Bacteria can decompose waste in an oxygen-deficient environment
Landfill gas = a mix of gases that consists of roughly half methane
Can be collected, processed, and used like natural gas
When not used commercially, landfill gas is burned off in flares to reduce odors and greenhouse emissions
Landfills after closure?
8000 in US in 1988
Today < 1,700
Fewer larger landfills
Thousands abandoned
Closed landfills often converted into public parks
Landfills have drawbacks
Leachate liquid that results when substances from the trash dissolve in water as rainwater percolates downward. They can eventually escape
The liner will become punctured
Leachate collection systems eventually aren't maintained
It is hard to find places suitable for landfills
The Not-In-My-Backyard (NIMBY) syndrome
The "Garbage barge" case
In 1987, Islip, New York's landfills were full, and a barge traveled to empty the waste in North Carolina, which rejected the load
It returned to Queens to incinerate the waste, after a 9,700 km (6,000 mile) global journey
Incineration
Incineration = a controlled process in which mixed garbage is burned at very high temperatures
Incineration in specially constructed facilities
Remaining ash must be disposed of in a hazardous waste landfill
Hazardous chemicals are created and released during burning
Scrubbers = chemically treat the gases produced in combustion to remove hazardous components and neutralize acidic gases
Many incinerators are WTE
Waste-to-energy facilities (WTE) = use the heat produced by waste combustion to create electricity
Companies contract with communities to guarantee a minimum amount of garbage
Long-term commitments interfere with the communities' later efforts to reduce waste
Bridgeport RESCO
11th largest in US

Reducing waste = better
Source reduction = preventing waste generation in the first place
Avoids costs of disposal and recycling
Helps conserve resources
Minimizes pollution
Can save consumers and businesses money

Much of the waste consists of materials used to package goods
Waste reduction: manufacturers
Can be reduced during manufacturing if consumers:
Choose minimally packaged goods
Buy unwrapped fruits and vegetables
Buy in bulk

Manufacturers can also:
Use packaging that is more recyclable
Reduce the size or weight of goods
Apple Computer
Legislating against waste
Plastic grocery bags
Grocery bags can take centuries to decompose
Choke and entangle wildlife
Litters the landscape
Many governments, federal state and local, have banned non-biodegradable bags
Westport was first in Connecticut
Reuse as a strategy?
Donate used items to resale centers
Other actions include:
Bring your own cup to coffee shops
Buy rechargeable batteries
Compost kitchen and yard wastes
Rent or borrow instead of buying
Home composting
Food and yard waste into composting piles, underground pits, or specially constructed containers
Heat from microbial action builds in the interior and decomposition proceeds
Decomposers (earthworms, bacteria, soil mites, sow bugs, and other organisms) convert waste into high-quality compost
Municipal composting
Divert food and yard waste from the waste stream to composting facilities
Reduces landfill waste
Encourages soil biodiversity
Reduces the need for chemical fertilizers
Makes healthier plants and more pleasing gardens

Recycling consists of three steps
Recycling = collecting materials that can be broken down and reprocessed to manufacture new items
Recycling diverts 58 million tons of materials away from incinerators and landfills each year
Step 1 in the recycling loop is collection and processing of recyclable materials through curbside recycling or designated locations
Materials recovery facilities (MRFs) = workers and machines sort items, then clean, shred and prepare them for reprocessing

The second and third steps of recycling
Step 2 is using recyclables to produce new products
Many products use recycled materials
In step 3, consumers purchase goods made from recycled materials
Must occur if recycling is to function
As markets expand, prices will fall
Recycling has grown rapidly
EPA: recycling is "one of the best environmental success stories of the late 20th century"
Recycling rates vary widely, depending on the product
67% of major appliances are recycled
Only 6% of plastics are recycled


Growth in recycling from:
A desire in municipalities to reduce waste output

The public's desire to expand recycling

New technologies and markets make recycling more and more cost effective
Recycling rates vary widely
Recycling is often not financially profitable because it is expensive to collect, sort and process recycled materials
And, the more material that is recycled, the lower the price
However, market forces do not take into account the health and environmental effects of not recycling
Enormous energy and material savings through recycling
Financial incentives
Pay-as-you-throw
The less waste a house generates the less it is charged for trash collection
Bottle bills
Challenges include including new kinds of containers and adjusting refunds for inflation
Industrial solid waste
U.S. industrial facilities generate 7.6 billion tons of waste
97% is wastewater
State or local governments regulate industrial solid waste
(with federal guidance)
Regulation and economics
Most methods and strategies of waste disposal, reduction, and recycling are similar to municipal solid waste
Regulation varies from state to state
In most cases, state and local regulations are less strict than federal rules
In many areas, industries are not required to have permits, install landfill liners or leachate collection systems, or monitor groundwater for contamination
Physical vs economic efficiency
Physical efficiency: the amount of waste generated by a manufacturing process
the less waste produced per unit or volume of product, the more efficient it is from a physical standpoint
Physical efficiency is not equal to economic efficiency
It can be cheaper to generate waste than to avoid waste
Rising cost of waste disposal can align these
Industrial ecology
Industrial ecology = redesigning industrial systems to reduce resource inputs and to minimize physical inefficiency while maximizing economic efficiency
Industrial systems should function like ecological systems, with little waste
Industrial ecology
Life cycle analysis = examine the life cycle of a product and look for ways to make the process more ecologically efficient
Waste products can be used as raw materials
Eliminating environmentally harmful products and materials
Look for ways to create products that are more durable, recyclable, or reusable
Beer ecology
The Swiss Zero Emissions Research and Initiatives (ZERI) Foundation sponsors innovative projects that create goods and services without generating waste
Hazardous waste
Ignitable = substances that easily catch fire (natural gas, alcohol)
Corrosive = substances that corrode metals in storage tanks or equipment
Reactive = substances that are chemically unstable and readily react with other compounds, often explosively or by producing noxious fumes
Toxic = substances that harm human health when they are inhaled, are ingested, or contact human skin
Major Sources of Hazardous waste
Industry
produces huge amounts of hazardous waste
Waste generation and disposal is highly regulated
Mining
Households
Paints, batteries, oils, solvents, cleaners, pesticides
Others
Small businesses
Agriculture
Organic compounds
Particularly hazardous because their toxicity persists over time
Synthetic organic compounds = resist decomposition
Keep buildings from decaying, kill pests, and keep stored goods intact
Their resistance to decay causes them to be persistent pollutants
They are toxic because they are readily absorbed through the skin
They can act as mutagens, carcinogens, teratogens, and endocrine disruptors
POPs: Persistent Organic Pollutants
Persistant synthetic chemicals, can bioaccumulate, and are environmental and human toxicants
Evidence of long-range transport of these substances to regions where they have never been used or produced
Consequent threats they pose to the environment of the whole globe
International calls for global actions to reduce and eliminate releases
Heavy metals
Lead, chromium, mercury, arsenic, cadmium, tin, and copper
Used widely in industry for wiring, electronics, metal plating, pigments, and dyes
They enter the environment when they are disposed of improperly
Heavy metals that are fat soluble and break down slowly can bioaccumulate and biomagnify

"E-waste"
Electronic waste ("e-waste") = waste involving electronic devices
Computers, printers, VCRs, fax machines, cell phones, iPods, Kindle, etc...
Frequently disposed of in landfills
should be treated as hazardous waste
metals and synthetic organic compounds


Disposal of hazardous waste
For many years, hazardous waste was discarded without special treatment
Public did not know it was harmful
Assumed substances disappear or be diluted
In 1980s, cities designate sites or special collection days
household hazardous waste only!
Disposal of hazardous waste
Federal Resource Conservation and Recovery Act (RCRA)
states are required to manage hazardous waste
Large generators of hazardous waste must obtain permits and must be tracked "from cradle to grave"
Intended to prevent illegal dumping
Dumping of hazardous waste
Since hazardous waste disposal is costly, it results in illegal and anonymous dumping by companies,
Creating health risks
Industrial nations illegally dump in developing nations
Basel Convention, an international treaty, should prevent dumping but it still happens
High costs of disposal encourages companies to invest in reducing their hazardous waste
Three disposal methods for hazardous waste landfills, surface impoundments, and injection wells
These methods do nothing to lessen the hazards of the substances
But they help keep the substance isolated from people, wildlife, and ecosystems
Landfills
Several impervious liners and leachate removal systems
Design and construction standards are stricter than for ordinary sanitary landfills
Must be located far from aquifers
Surface impoundments
Liquid hazardous waste or waste in dissolved form may be stored in one of these.
It's shallow depressions are lined with plastic and clay
Water containing waste evaporates, the residue of solid hazardous waste is then transported elsewhere
The underlying clay layer can crack and leak waste, and rainstorms cause overflow, contaminating nearby areas
Deep-well injection
A long-term disposal method
The well is intended to be isolated from groundwater and human contact
However, the wells become corroded and leak waste into soil
Radioactive waste
Yucca Mountain in Nevada is now designated as the single-site repository for all U.S. nuclear waste
The Waste Isolation Pilot Plant (WIPP) is the world's first underground repository for transuranic waste from nuclear weapons development
Caverns holding the waste are 655 m (2,150 ft) below ground in a huge salt formation thought to be geologically stable
WIPP became operational in 1999 and is receiving thousands of shipments of waste
Contaminated sites
Comprehensive Environmental Response Compensation and Liability Act (CERCLA) (1980)
Superfund
Established a federal program to clean up U.S. sites polluted with hazardous waste
Experts identify polluted sites, take action to protect groundwater near these sites, and clean up the pollution
Superfund
Two events spurred creation of Superfund legislation
In Love Canal, Niagara Falls, New York, buried toxic chemicals rose to the surface, contaminating homes and an elementary school
In Times Beach, Missouri, contaminated with dioxin from waste oil sprayed on roads
Later laws charged EPA with brownfields
lands whose reuse or development are complicated by the presence of hazardous materials
The Superfund process
Once a Superfund site is identified, EPA scientists evaluate:
How close the site is to human habitation
Whether wastes are currently confined or likely to spread
Whether the site threatens drinking water supplies
Superfund
Harmful sites are:
Placed on the EPA's National Priority List
Ranked according to the level of risk to human health that they pose
Cleaned up on a site-by-site basis as funds are available
The EPA is required to hold public hearings and inform area residents of tits findings and to receive feedback
Who pays for cleanup?
An average cleanup costs $25 million and takes 12 - 15 years
Polluter pays principle = polluting parties were to be charged for cleanup
Responsible parties often can't be found
A trust fund was established by a federal tax on petroleum and chemical industries
The fund is bankrupt, and neither the Bush administration nor Congress has moved to restore it, so taxpayers now pay all costs of cleanup
Conclusion
Our societies have made great strides in addressing our waste problems
Modern methods of waste management are far safer for people and gentler on the environment
Recycling and composting are growing rapidly
Our prodigious consumption had created more waste than ever before
Finding ways to reduce, reuse and efficiently recycle the materials and goods that we use stands as a key challenge for the new century
The Urban Environment: Creating Sustainable Cities
Case Study
Urban growth boundary (UGB): a line on a map intended to separate areas desired to be urban from areas desired to remain rural
Our Urbanizing World
Urbanization: shift from the countryside into towns and cities
Industrialization has driven urbanization
Suburbs: smaller communities thing ring the cities
Environmental factors influence the location of urban area
Location
Climate
Topography
Configuration of waterways
People have moved to suburbs
In developed nations
Sprawl
The spread of low-density urban or suburban development outward from an urban center
Urban areas spread outward
The physical spread of development at the rate that exceeds the rate of population growth
Sprawl has several causes
Human population growth (there are more of us alive each year)
Per capita land consumption (each person is taking up more land than in the past
What is wrong with sprawl?
Transportation- forcing people to own a car, drive to places further
Pollution - higher car use, motor oil, road salt all runoff and pollute waterways
Health -physical inactivity
Land use - less area for forests, fields, farmland, or ranchland
Economics- drains tax dollars, money goes to infrastructure
Creating Livable Cities
Planning helps to create livable urban cities
City planning: the professional pursuit that attempts to design cities in such a way as to maximize their efficiency, functionality, and beauty. Also known as urban planning
Regional planning: deals with the same issues as city planners, but they work on broader geographic scales and coordinate their work their work with multiple municipal governments
Zoning is a key tool for planning
Zoning: the practice of classifying area for different types of development and land use
Urban Growth boundaries are now widely used:
Urban Growth Boundaries (UGBs): aim to revitalize downtown, protect working farms, orchard, ranches, and forests, and ensure urban dwellers access to open space
"Smart Growth" and "new urbanism" aim to counter sprawl
smart growth: a city planning concept in which a community's growth is managed in ways intended to limit sprawl and maintain or improve resident's quality of life
New urbanism: seeks to design walkable neighborhoods with homes, businesses, schools and other amenities all close together for convenience


Transit options help cities
Mass transit: public systems of buses, trains, subways, or light rails that move large numbers of people at once while easing traffic congestion, taking up less space, and emitting less pollution
Urban residents need parklands
Green building bring benefits
Green building: structures that are built from sustainable materials. Limit their use of energy and water, minimize health impacts on their occupants, control pollution, and recycle waste
Leadership in Energy and Environmental Design (LEED): the leading set of standards for sustainable building.
Urban Sustainability
Urban centers bring a mix of environmental effects
Resource use and efficiency
Pollution
Urban heat island effect: the phenomenon whereby a city becomes warmer than outlying areas because of the concentration of heat generating buildings, vehicles, and people, and because buildings and dark paved surfaces absorb heat and release it at night
Land preservation
Innovation
Urban ecology helps cities toward sustainability
Urban ecology: a scientific field of study that views cities explicitly as ecosystems. Researchers in this field apply the fundamentals of ecosystem ecology and systems science to urban areas
Follow an ecosystem-centered model by striving for:
1. max efficient use of resources
2. recycle as much as possible
3. develop environmentally friendly tech
4. account full for external costs
5. use tax incentives to encourage sustainable practices
6. use locally produced resources
7. apply organic waste and wastewater to restore soil fertility
8. encourage urban agriculture
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